Selective Service SSS Form 1-A for Joseph R. Biden, February 15, 1961; Selective Service System. New York City Headquarters. 1940-1975, Record Group 147, Records of the National Archives and Records Administration; National Archives at St. Louis, St. Louis, MO. (digital scanned reproduction).
Selective Service SSS Form 102 for Joseph R. Biden; Selective Service System. New York City Headquarters. 1940-1975, Record Group 147, Records of the National Archives and Records Administration; National Archives at St. Louis, St. Louis, MO. (Entry for Joseph R. Biden is on line #29) (digital scanned reproduction).
See definitions for Selective Service classification codes.