. . "A Guide to Understanding Audit in Trusted Systems"@en . . "U.S. Department of Defense, A Guide to Understanding Audit in Trusted Systems (NCSC-TG-001) (July 28, 1987) (known as the \"Tan Book\") (full-text)."@en . . . "U.S. Department of Defense, A Guide to Understanding Audit in Trusted Systems (NCSC-TG-001) (July 28, 1987) (known as the \"Tan Book\") (full-text)."@en .