Study resources

Calculators

Both work in your browser and send nothing anywhere. Perfume Dilution Basics teaches the arithmetic behind them; do it by hand a few times first.

Where to look things up

• The material encyclopedia

  Odor profile, identity, handling and formula usage for individual materials.

• The formula library

  Published formulas and accords, every ingredient linked to its material.

• The Lab blog

  Reference guides on calculation, records, regulation and more.

• The perfumery glossary

  The working vocabulary of perfume formulation.

• The RUŌOD Journal

  Perfume for people who wear it: notes, families, history and buying.

• The RUŌOD Lab application

  An Android app for keeping a material library and calculating formulas.

Sources cited in the lessons

• 18 U.S. Code § 1836 (Defend Trade Secrets Act civil action) — The US federal civil remedy for trade secret misappropriation. Cited in Confidentiality, Trade Secrets and What Protects a Formula.
• Adams RP. Identification of Essential Oil Components by Gas Chromatography/Mass Spectrometry, 4th edition. Allured, 2007 — A standard reference on 5%-phenyl-type column data.. Cited in How a GC Column Separates a Fragrance, Reading a Mass Spectrum, Retention Indices and Identification, Coelution, Isomers and False Identifications, Fingerprinting Natural Materials, Specialist Project: An Analytical Dossier, Fragmentation Mechanisms in Terpenoid Mass Spectra, Reconstruction as a Research Method.
• Arthur CL, Pawliszyn J. Solid phase microextraction with thermal desorption using fused silica optical fibers. Anal Chem 62(19):2145–2148, 1990. Cited in Headspace Sampling Methods Compared.
• ASTM F2417, Standard Specification for Fire Safety for Candles — An example of a candle fire safety standard. Check the current edition, and the rules in your market.. Cited in Candles and Air Care Engineering.
• Atkins P, de Paula J, Keeler J. Atkins' Physical Chemistry (Oxford University Press) — Raoult's law, Henry's law, activity and real solutions; any recent edition. Cited in Raoult's Law and the Headspace of a Perfume, Evaporation Thermodynamics: Clausius–Clapeyron at the Blotter, Autoxidation Kinetics and Accelerated Aging.
• Brattoli et al. (2013), Gas chromatography analysis with olfactometric detection (GC-O), Sensors — overview of GC-O as a methodology. Cited in Correlating Sensory and Analytical Data.
• Brattoli M, et al. Gas chromatography analysis with olfactometric detection (GC-O) as a useful methodology for chemical characterization of odorous compounds. Sensors 13:16759–16800, 2013. Cited in Gas Chromatography-Olfactometry.
• Brattoli M, et al. Gas chromatography analysis with olfactometric detection. Sensors 13:16759–16800, 2013. Cited in Headspace Sampling Methods Compared.
• Busse D, et al. A synthetic sandalwood odorant induces wound-healing processes in human keratinocytes via the olfactory receptor OR2AT4. J Invest Dermatol 134(11):2823–2832, 2014. Cited in Sandalwood Odorants, Reading Fragrance Research Critically.
• Calkin and Jellinek (1994), Perfumery: Practice and Principles, Wiley — general reference on composition. Cited in Rose Accord Workshop, Vapor Pressure: The Physics Behind Volatility.
• Calkin RR, Jellinek JS. Perfumery: Practice and Principles. Wiley, 1994. Cited in Reduction: The Fewest Materials That Still Work, Partitioning and Release in Functional Products, Chemical Survival in Harsh Bases, Advanced Accord Architecture, Texture, Contrast and Diffusion as Design Variables, Originality, Signature and the Luxury Brief, Mastery Project: A Signature Composition and Its Mod Tree, Evaluation in Fragrance-House Development, Formula Economics: Cost in Use, Creative Leadership and the Professional Submission.
• Canada Gazette: SOR/2024-63 — Canadian allergen labeling, with thresholds of 0.01% and 0.001%.. Cited in Allergen Calculation in Depth, Building a Market Requirements Matrix.
• CAS Registry, Chemical Abstracts Service — what the registry is. Cited in Read a Material's CAS Number and SDS, A Data Model for Formulas and Materials.
• CITES: Convention on International Trade in Endangered Species. Cited in Sustainable Ingredient Innovation.
• Clayden J, Greeves N, Warren S. Organic Chemistry (Oxford University Press) — Hemiacetals, acetals, imines and ester exchange: mechanisms and equilibria. Cited in Equilibria in the Bottle: Acetals, Schiff Bases and Esters.
• Cornell JA. Experiments with Mixtures: Designs, Models and the Analysis of Mixture Data (Wiley) — The standard reference text. Cited in Mixture Designs for Accords.
• d'Acampora Zellner B, et al. Gas chromatography-olfactometry in food flavour analysis. J Chromatogr A 1186:123–143, 2008. Cited in Gas Chromatography-Olfactometry.
• d'Acampora Zellner et al. (2008), Gas chromatography-olfactometry in food flavour analysis, Journal of Chromatography A 1186, 123-143 — review of GC-O methods. Cited in Correlating Sensory and Analytical Data.
• Delon-Martin et al. (2013), Perfumers' expertise induces structural reorganization in olfactory brain regions, NeuroImage — gray-matter differences in professional perfumers, some tracking years of experience. Cited in Odor Recognition Drills That Work.
• Directive (EU) 2016/943 on the protection of undisclosed know-how and business information (trade secrets) — Definition, lawful acquisition including reverse engineering, remedies; read on 2026-11-03. Cited in Confidentiality, Trade Secrets and What Protects a Formula.
• Directive (EU) 2024/825 on empowering consumers for the green transition — EU rules on environmental claims, adopted 2024. Check how it has been applied in your market.. Cited in Biotechnology-Derived Ingredients, Sustainable Ingredient Innovation.
• EN 16274 (2021 edition): quantification of suspected fragrance allergens by GC-MS — An example of an analytical method. Check its current scope against the current list.. Cited in Allergen Calculation in Depth.
• EN 16274: Methods for analysis of allergens. Quantification of suspected fragrance allergens in consumer products. Step 1: GC analysis of ready-to-inject sample — The 2012 edition was withdrawn in 2021, and a 2021 edition replaces it. It is an example of a formal method using two columns of different polarity.. Cited in Quantification Limits: What Area Percent Means.
• Ennis DM. The power of sensory discrimination methods. Journal of Sensory Studies 8(4):353–370, 1993 — Power and sample size of discrimination methods in a Thurstonian framework. Cited in Discrimination Tests and Thurstonian d′.
• European Commission: Cosmetics. Cited in European Union: Study Guide.
• European Commission: Fragrance allergens labelling — 56 additional allergens; dates of July 31, 2026 and July 31, 2028.. Cited in Fragrance Allergens: Study Guide, Allergen Calculation in Depth.
• Friedman and Miller (1971), Odor incongruity and chirality, Science 172, 1044-1046 — carvone enantiomers. Cited in Structure-Odor Relationships, Stereochemistry and Smell.
• Friedman L, Miller JG. Odor incongruity and chirality. Science 172:1044–1046, 1971. Cited in Enantiomers in Depth: What the Evidence Shows.
• Gerkin and Castro (2015), The number of olfactory stimuli that humans can discriminate is still unknown, eLife — reanalysis of the one-trillion claim. Cited in How Smell Works: What a Perfumer Needs to Know.
• GOV.UK: Making cosmetic products available to consumers in Great Britain — Checked October 9, 2026 per this site's reference log.. Cited in United Kingdom: Study Guide, Building a Fragrance Compliance File, Building a Market Requirements Matrix.
• Grosch W. Evaluation of the key odorants of foods by dilution experiments, aroma models and omission. Chemical Senses 26(5):533–545, 2001 — OAV = concentration over odor threshold; omission and recombination as the check; exceptions where high-OAV odorants are suppressed. Cited in Odor Activity Values: From Concentration to Impact, Ingredient Interactions in Complex Mixtures, Reconstruction as a Research Method.
• Grosofsky, Haupert and Versteeg (2011), An exploratory investigation of coffee and lemon scents and odor identification, Perceptual and Motor Skills 112(2), 536-538 — no advantage for coffee beans over lemon or air. Cited in Olfactory Fatigue: How to Rest Your Nose.
• Hazard Communication, US Occupational Safety and Health Administration — the US standard behind SDS format. Cited in Read a Material's CAS Number and SDS, Safe Handling of Perfumery Materials at Home.
• Help and enquiries, International Fragrance Association (IFRA) — IFRA does not run perfumery courses and refers enquirers to schools. Cited in How Professional Perfumers Work.
• Hillier FS, Lieberman GJ. Introduction to Operations Research (McGraw-Hill) — Linear programming, the simplex method and sensitivity analysis; any recent edition. Cited in Optimization Under Constraints: Cost and Composition.
• History of fragrance, Société Française des Parfumeurs-Créateurs — trade overview, used for Perkin's coumarin and its use in Fougère Royale. Cited in How New Materials Changed Perfumery, Next Steps and Formal Training Routes.
• Hummel et al. (2009), Effects of olfactory training in patients with olfactory loss, Laryngoscope 119(3), 496-499 — clinical study: four odors twice daily for 12 weeks. Cited in A Daily Olfactory Training Routine.
• IFEAT Academy — professional distance-learning units for the aroma trades. Cited in How Professional Perfumers Work, Next Steps and Formal Training Routes, Evaluation in Fragrance-House Development.
• IFRA, Guidance for the use of the IFRA Standards (51st Amendment, June 30, 2023) — how phototoxicity and other restrictions are applied. Cited in Citrus Accord Workshop, Evaluate on Strip, Skin and Fabric, Oxidation and Degradation Pathways, IFRA Standards: Study Guide, Constituents of Naturals in Restriction Checks.
• IFRA: Certification of IFRA Standards. Cited in IFRA Certificates: Study Guide.
• IFRA: End of consultation letter for the 52nd Amendment (August 31, 2026) — Consultation ran December 12, 2025 to June 12, 2026; notification expected January 2027.. Cited in Amendment Awareness.
• IFRA: Guidance for the use of the IFRA Standards (51st Amendment, June 30, 2023) — Category tables and product placement. A newer edition may replace it.. Cited in IFRA Categories and QRA: Study Guide, Amendment Awareness, Phototoxicity: Study Guide, Soap and Alkaline Systems, Laundry and Fabric Care, Shampoo, Shower and Surfactant Systems, Candles and Air Care Engineering, Constituents of Naturals in Restriction Checks.
• IFRA: IFRA Standards. Cited in IFRA Standards: Study Guide.
• ISO 14040:2006, Environmental management: Life cycle assessment, principles and framework. Cited in Sustainable Ingredient Innovation.
• ISO 22716: Cosmetics, Good Manufacturing Practices. Cited in Specifications and Release Testing, Deviations and Corrective Action, GMP Thinking for Small Makers, Supplier Qualification and Raw-Material Specifications, Industrial Compounding and Scale-Up.
• ISO 3515: Essential oil of lavender — An example of a standard with a composition profile. Check the current edition.. Cited in Fingerprinting Natural Materials, Supplier Qualification and Raw-Material Specifications.
• ISO 4120:2021, Sensory analysis: Methodology: Triangle test — the formal method. This exercise is informal practice, not an application of the standard.. Cited in Blind Smelling Practice for Beginners, Comparative Evaluation: Choosing the Right Test, Sample Size and Sensory Statistics, Discrimination Tests and Thurstonian d′, Mastery Project: A Statistical Study of One Accord.
• ISO/TR 18811:2018, Cosmetics: Guidelines on the stability testing of cosmetic products — reviews existing references. It leaves the protocol for the manufacturer to specify and justify.. Cited in Stability Testing: Study Guide and Study Design, Interpreting a Failed Stability Test, Autoxidation Kinetics and Accelerated Aging, Mastery Project: A Physical-Chemistry Dossier.
• Jaeger SR, et al. A Mendelian trait for olfactory sensitivity affects odor experience and food selection. Curr Biol 23(16):1601–1605, 2013. Cited in Receptor Genetics and Individual Differences.
• JCGM 100:2008. Evaluation of measurement data — Guide to the expression of uncertainty in measurement (GUM). BIPM — Type A and Type B evaluations, combined and expanded uncertainty. Cited in Measurement Uncertainty in Weighing and Dilution, Mastery Project: A Statistical Study of One Accord, Industrial Compounding and Scale-Up.
• Jolliffe IT, Cadima J. Principal component analysis: a review and recent developments. Philosophical Transactions of the Royal Society A 374:20150202, 2016 — What PCA does, what it cannot do, and its variants. Cited in Regression and Principal Component Analysis of Panel Data.
• Karlberg AT, Magnusson K, Nilsson U. Air oxidation of d-limonene (the citrus solvent) creates potent allergens. Contact Dermatitis 26(5):332–340, 1992 — Oxidation products of limonene and their sensitizing capacity in animal tests. Cited in Autoxidation Kinetics and Accelerated Aging.
• Keller A, et al. Predicting human olfactory perception from chemical features of odor molecules. Science 355(6327):820–826, 2017 — DREAM Olfaction Prediction Challenge; 49 people and 476 molecules.. Cited in AI in Perfume Research and Formulation: Uses and Limits, Predicting Odor from Structure, Validating Odor-Prediction Models.
• Keller A, Zhuang H, Chi Q, Vosshall LB, Matsunami H. Genetic variation in a human odorant receptor alters odour perception. Nature 449:468–472, 2007. Cited in Receptor Genetics and Individual Differences.
• Keller et al. (2017), Predicting human olfactory perception from chemical features of odor molecules, Science 355(6327), 820-826 — the crowdsourced DREAM challenge. Cited in Structure-Odor Relationships.
• Keller, Zhuang, Chi, Vosshall and Matsunami (2007), Genetic variation in a human odorant receptor alters odour perception, Nature 449, 468-472 — OR7D4 and androstenone. Cited in What Receptor Research Does and Does Not Explain.
• Kraft P, Bajgrowicz JA, Denis C, Fráter G. Odds and trends: recent developments in the chemistry of odorants. Angew Chem Int Ed 39(17):2980–3010, 2000. Cited in The Musk Problem: Many Structures, One Odor, Sandalwood Odorants, Ambergris-Type Odorants, Specialist Project: A Structure-Odor Review, Molecular Descriptors for Odorants.
• Laing DG, Francis GW. The capacity of humans to identify odors in mixtures. Physiol Behav 46(5):809–814, 1989. Cited in Mixture Perception, Odor Activity Values: From Concentration to Impact, Ingredient Interactions in Complex Mixtures.
• Laska (2004), Olfactory discrimination ability of human subjects for enantiomers with an isopropenyl group at the chiral center, Chemical Senses 29(2), 143-152 — 20 subjects, nine pairs, forced-choice triangle test. Cited in Stereochemistry and Smell.
• Laska M. Olfactory discrimination ability of human subjects for enantiomers with an isopropenyl group at the chiral center. Chem Senses 29(2):143–152, 2004. Cited in Enantiomers in Depth: What the Evidence Shows.
• Lawless HT, Heymann H. Sensory Evaluation of Food: Principles and Practices. Springer — Food-focused, with methods relevant to fragrance evaluation.. Cited in From Curiosity to a Testable Question, Sample Size and Sensory Statistics, Mixture Designs for Accords, Discrimination Tests and Thurstonian d′, Regression and Principal Component Analysis of Panel Data, Texture, Contrast and Diffusion as Design Variables, Evaluation in Fragrance-House Development.
• Lee BK, et al. A principal odor map unifies diverse tasks in olfactory perception. Science 381:999–1006, 2023. Cited in Predicting Odor from Structure, Validating Odor-Prediction Models.
• Mainland JD, et al. The missense of smell: functional variability in the human odorant receptor repertoire. Nat Neurosci 17(1):114–120, 2014. Cited in Receptor Genetics and Individual Differences.
• Matura et al. (2005), Selected oxidized fragrance terpenes are common contact allergens, Contact Dermatitis 52(6), 320-328 — patch-test study of oxidized terpenes. Cited in How to Store Perfume Materials, Oxidation and Degradation Pathways, Autoxidation Kinetics and Accelerated Aging.
• McLafferty FW, Tureček F. Interpretation of Mass Spectra, 4th edition. University Science Books, 1993 — The standard text on fragmentation mechanisms. Cited in Fragmentation Mechanisms in Terpenoid Mass Spectra.
• Meilgaard MC, Civille GV, Carr BT. Sensory Evaluation Techniques. CRC Press — A widely used handbook. Use the latest edition you can reach.. Cited in From Curiosity to a Testable Question, Regression and Principal Component Analysis of Panel Data.
• NIST Chemistry WebBook — Free reference spectra for many fragrance compounds.. Cited in Reading a Mass Spectrum, Specialist Project: An Analytical Dossier, Raoult's Law and the Headspace of a Perfume, Evaporation Thermodynamics: Clausius–Clapeyron at the Blotter, Fragmentation Mechanisms in Terpenoid Mass Spectra, Mastery Project: A Physical-Chemistry Dossier.
• NIST Chemistry WebBook, Gas Chromatographic Retention Data — published retention indices for non-polar and slightly polar phases. Cited in How to Read a GC-MS Report, How a GC Column Separates a Fragrance, Retention Indices and Identification, Coelution, Isomers and False Identifications.
• Ohloff G, Pickenhagen W, Kraft P. Scent and Chemistry, 2nd edition. Wiley-VCH, 2011. Cited in The Musk Problem: Many Structures, One Odor, Sandalwood Odorants, Ambergris-Type Odorants, Enantiomers in Depth: What the Evidence Shows, Specialist Project: A Structure-Odor Review, Equilibria in the Bottle: Acetals, Schiff Bases and Esters.
• Ohloff G, Vial C, Wolf HR, Job K, Jégou E, Polonsky J, Lederer E. Stereochemistry-odor relationships in enantiomeric ambergris fragrances. Helv Chim Acta 63:1932–1946, 1980. Cited in Ambergris-Type Odorants.
• Perfume and Flavor Engineering: A Chemical Engineering Perspective. Molecules, 2021 (review) — Reviews evaporation and diffusion models built on vapor-liquid equilibrium and Fick's law. Cited in Raoult's Law and the Headspace of a Perfume, Evaporation Thermodynamics: Clausius–Clapeyron at the Blotter.
• Pro Git, Chacon S, Straub B (Apress, free online edition) — Version control concepts: commits, history and diffs. Cited in Diffing Formula Versions.
• PubChem, National Library of Medicine — structures and molecular formulas for checking. Cited in Reading a Molecular Structure, Vapor Pressure: The Physics Behind Volatility, Partitioning and Release in Functional Products, Mastery Project: A Physical-Chemistry Dossier, Molecular Descriptors for Odorants.
• Ravia A, et al. A measure of smell enables the creation of olfactory metamers. Nature 588:118–123, 2020. Cited in Predicting Odor from Structure, Mixture Perception.
• RDKit: open-source cheminformatics (rdkit.org) — The toolkit used in the exercise; its Descriptors module includes MolLogP (Wildman–Crippen) and TPSA. Cited in Molecular Descriptors for Odorants.
• Regulation (EC) No 1223/2009 on cosmetic products. Cited in European Union: Study Guide, Building a Fragrance Compliance File, GMP Thinking for Small Makers, Building a Market Requirements Matrix.
• Regulation (EC) No 1272/2008 (CLP) — Revised by Regulation (EU) 2024/2865, with later amended application dates. Check the current text.. Cited in SDS and CLP for Fragrance Oils: Study Guide.
• Regulation (EC) No 1907/2006 (REACH). Cited in SDS and CLP for Fragrance Oils: Study Guide, Supplier Qualification and Raw-Material Specifications.
• Regulation (EU) 2016/679 (GDPR) — EU data protection rules. Check the law where you are.. Cited in Ethics of Testing on People.
• Regulation (EU) 2017/1410 — prohibition of HICC, atranol and chloroatranol. Cited in Muguet Without Lilial: Study Guide, Fougère Accord Workshop.
• Regulation (EU) 2021/1902 — prohibition of butylphenyl methylpropional in EU cosmetics. Cited in Muguet Without Lilial: Study Guide.
• Regulation (EU) 2022/1176 — EU limits and labeling for benzophenone-3. Cited in Antioxidants and UV Absorbers: Study Guide.
• Regulation (EU) 2022/2195 — EU limits for BHT in cosmetics. Cited in Antioxidants and UV Absorbers: Study Guide.
• Regulation (EU) 2023/1545. Cited in Fragrance Allergens: Study Guide, Allergen Calculation in Depth.
• Regulation (EU) 2023/2055, restriction of synthetic polymer microparticles — In force October 17, 2023. A transition for fragrance encapsulation is reported to run to October 17, 2029.. Cited in Laundry and Fabric Care.
• Regulation (EU) 2026/405 on detergents and surfactants — Published March 2, 2026, applying from September 23, 2029. Replaces Regulation (EC) 648/2004. Check its current position.. Cited in Chemical Survival in Harsh Bases, Laundry and Fabric Care.
• RUŌOD Lab application — Described from the app's own source code and documentation as checked on 2026-11-03; Android only. Cited in RUŌOD Lab Tutorial: Materials, Collections and Fields, RUŌOD Lab Tutorial: Dilution Methods, Scaling and Targets, RUŌOD Lab Tutorial: Versions, History, Reports and Exports.
• SCCS opinion on QRA2 (adopted July 30, 2018) — An EU scientific committee's critical view: it judged that QRA2 could not yet be used to set a concentration at which induction is unlikely.. Cited in IFRA Categories and QRA: Study Guide.
• Scheffé H. Experiments with mixtures. Journal of the Royal Statistical Society, Series B 20(2):344–360, 1958 — The original theory of mixture experiments, designs and canonical polynomials. Cited in Mixture Designs for Accords, Mastery Project: A Statistical Study of One Accord.
• Shirasu M, et al. Olfactory receptor and neural pathway responsible for highly selective sensing of musk odors. Neuron 81(1):165–178, 2014. Cited in The Musk Problem: Many Structures, One Odor.
• Sköld, Börje, Matura and Karlberg (2002), Studies on the autoxidation and sensitizing capacity of the fragrance chemical linalool, identifying a linalool hydroperoxide, Contact Dermatitis — autoxidation is what makes linalool sensitizing in this animal study. Cited in How to Store Perfume Materials, Autoxidation Kinetics and Accelerated Aging.
• Smell Disorders, National Institute on Deafness and Other Communication Disorders — how smell reaches the sensory cells; hyposmia and anosmia. Cited in How Smell Works: What a Perfumer Needs to Know, A Daily Olfactory Training Routine.
• Snitz et al. (2013), Predicting odor perceptual similarity from odor structure, PLOS Computational Biology — predicting mixture similarity. Cited in Structure-Odor Relationships.
• Snitz K, et al. Predicting odor perceptual similarity from odor structure. PLOS Computational Biology, 2013. Cited in AI in Perfume Research and Formulation: Uses and Limits, Predicting Odor from Structure, Validating Odor-Prediction Models.
• Stevens SS. On the psychophysical law. Psychological Review 64(3):153–181, 1957 — The power law of perceived magnitude. Cited in Odor Activity Values: From Concentration to Impact.
• Strang G. Introduction to Linear Algebra (Wellesley-Cambridge Press) — Matrix equations, solvability and least squares; any recent edition. Cited in A Formula as a Linear System.
• Surburg and Panten, Common Fragrance and Flavor Materials, Wiley-VCH — standard reference organized by chemical class. Edition not checked; consult the latest.. Cited in Functional Groups: A Working Guide for Perfumers, Equilibria in the Bottle: Acetals, Schiff Bases and Esters.
• Teixeira MA, Rodríguez O, Rodrigues AE. Perfumery Radar: a predictive tool for perfume family classification. Ind Eng Chem Res 49:11764–11777, 2010 — A perfume classified from its liquid composition and the vapor-liquid behavior of its ingredients. Cited in Raoult's Law and the Headspace of a Perfume.
• The Belmont Report (US, 1979) — Sets out respect for persons, beneficence and justice.. Cited in Ethics of Testing on People.
• The Nobel Prize in Physiology or Medicine 2004, press release — Axel and Buck's discovery of odorant receptors; about 1,000 genes in their work on the mouse. Cited in How Smell Works: What a Perfumer Needs to Know, What Receptor Research Does and Does Not Explain.
• The Python Tutorial (Python Software Foundation) — The language features used here: functions, dataclasses, lists and assertions. Cited in Fragrance Calculations in Python, Checked.
• Thomas-Danguin T, et al. The perception of odor objects in everyday life: a review on the processing of odor mixtures. Frontiers in Psychology 5:504, 2014 — Mixtures perceived as unified odor objects or as separable parts. Cited in Advanced Accord Architecture, Ingredient Interactions in Complex Mixtures.
• Trimmer C, et al. Genetic variation across the human olfactory receptor repertoire alters odor perception. PNAS 116(19):9475–9480, 2019. Cited in Receptor Genetics and Individual Differences.
• US FDA: Modernization of Cosmetics Regulation Act of 2022 (MoCRA) — Checked October 9, 2026, per this site's reference log. Check for updates, including final allergen and GMP rules.. Cited in United States, MoCRA: Study Guide, Building a Fragrance Compliance File, GMP Thinking for Small Makers, Building a Market Requirements Matrix.
• USPS Publication 52 — US mailing rules, including flammable liquids. Cited in Flash Point in Context: Study Guide.
• van den Dool and Kratz (1963), A generalization of the retention index system, Journal of Chromatography 11, 463-471 — retention indices in temperature-programmed GC. Cited in How to Read a GC-MS Report.
• van den Dool H, Kratz PD. A generalization of the retention index system including linear temperature programmed gas-liquid partition chromatography. J Chromatogr 11:463–471, 1963. Cited in Retention Indices and Identification, Fragmentation Mechanisms in Terpenoid Mass Spectra.
• van Ruth SM. Methods for gas chromatography-olfactometry: a review. Biomol Eng 17:121–128, 2001. Cited in Gas Chromatography-Olfactometry.
• Weiss T, et al. Perceptual convergence of multi-component mixtures in olfaction implies an olfactory white. PNAS 109:19959–19964, 2012. Cited in Mixture Perception, Ingredient Interactions in Complex Mixtures.
• Whissell-Buechy D, Amoore JE. Odour-blindness to musk: simple recessive inheritance. Nature 242:271–273, 1973 — An early study; later genetic work shows more complexity.. Cited in The Musk Problem: Many Structures, One Odor.
• Wilkinson MD, et al. The FAIR Guiding Principles for scientific data management and stewardship. Scientific Data 3:160018, 2016 — The principles and their rationale. Cited in A Data Model for Formulas and Materials, Mastery Project: A Reproducible Computational Record, Mastery Capstone: An Original Fragrance Research Project.
• WIPO Magazine: Copyright in the Courts: Perfume as Artistic Expression? — Including the Dutch Supreme Court's 2006 Kecofa v Lancôme decision. Cited in Reconstruction as a Research Method, Confidentiality, Trade Secrets and What Protects a Formula.
• World Medical Association. Declaration of Helsinki, revision adopted October 2024 — A framework for medical research involving human participants. It's not written for informal fragrance tests, but its principles are a useful guide.. Cited in Ethics of Testing on People, Mastery Capstone: An Original Fragrance Research Project.