The world depends on a collection of strange items. They're not cheap
What is a Standard Reference Material or SRM?
The US government will sell you freeze-dried urine
Understanding the Types of Reference Materials, Their Differences, and Their Uses
Reference Standards, Types, Uses, Preparation & Qualification
Reference Materials: An Introduction to quality grades and an overview on the different types for...
Secondary Standards as Certified Reference Materials
4th Grade Reference Materials
National Register Guide, Episode12: Standard Reference Materials
The INSANE Precision of The National Institute of Standards and Technology
Certified Reference Materials
How to choose the correct reference material quality grade for your needs
GOA-ON in a Box: How and Why to Use Certified Reference Materials (English)
Making an international standard cup of tea
Quality Control Reference Material
Chemical Standards, Reference Material...
Reference Standards
Certified Reference Material in detail
Metrological Traceability | CRM | Certified Reference Material
Reference Materials, The System of Certified Reference Materials Production in Russia (2017)