32 C.F.R. § 2001.22
(b) Identity of persons who apply derivative classification markings. Derivative classifiers shall be identified by name and position, or by personal identifier, in a manner that is immediately apparent on each derivatively classified document. If not otherwise evident, the agency and office of origin shall be identified and follow the name on the “Classified By” line. An example might appear as:
Classified By: Peggy Jones, Lead Analyst, Research and Analysis Division or Classified By: ID # IMN01
(c) Source of derivative classification.
(1) The derivative classifier shall concisely identify the source document or the classification guide on the “Derived From” line, including the agency and, where available, the office of origin, and the date of the source or guide. An example might appear as:
Derived From: Memo, “Funding Problems,” October 20, 2008, Office of Administration, Department of Good Works or Derived From: CG No. 1, Department of Good Works, dated October 20, 2008
(i) When a document is classified derivatively on the basis of more than one source document or classification guide, the “Derived From” line shall appear as:
Derived From: Multiple Sources
(2) A document derivatively classified on the basis of a source document that is itself marked “Multiple Sources” shall cite the source document on its “Derived From” line rather than the term “Multiple Sources.” An example might appear as:
Derived From: Report entitled, “New Weapons,” dated October 20, 2009, Department of Good Works, Office of Administration
(e) Declassification instructions.
(3) When a document is classified derivatively either from a source document(s) or a classification guide that contains one of the following declassification instructions, “Originating Agency's Determination Required,” “OADR,” or “Manual Review,” “MR,” or any of the exemption markings X1, X2, X3, X4, X5, X6, X7, and X8, the derivative classifier shall calculate a date that is 25 years from the date of the source document when determining a derivative document's date or event to be placed in the “Declassify On” line.
(4) When determining the most restrictive declassification instruction among multiple source documents, adhere to the following hierarchy for determining the declassification instructions for the “Declassify On” line: