Secretary of Defense to the Assistant to the President for National Security Affairs, “Communications Between the US and USSR In Time of Crisis,” with attachments including the 30 September 1976 “Protocol on the Use of Immediate Notifications in the Implementation of the Agreement on Measures to Reduce the Risk of Outbreak of Nuclear War Between the United States of America and the Union of Soviet Socialist Republics of September 30, 1971,” Secret, n.d. [Circa 1976-1977]