32 CFR 2400.16: Derivative classification markings.
(a) Documents classified derivatively on the basis of source documents or classification guides shall bear all markings prescribed in § 2400.12 of this part and Directive No. 1 as are applicable. Information for these markings shall be taken from the source document or instructions in the appropriate classification guide. When markings are omitted because they may reveal a confidential source or relationship not otherwise evident, as described in § 2400.12 of this part, the information may not be used as a basis for derivative classification.
(b) The authority for classification shall be shown as directed in Directive No. 1.