All information required for the official use of a USP RS is provided in the associated USP compendial procedure. https://www.usp.org/sites/default/files/usp/document/our-work/reference-standards/qa-policy-statement-usp-rs-certificates-and-assigned-values.pdf
For further information and support please go to the website of the issuing Pharmacopoeia
https://www.usp.org/reference-standards