US. Congress. (1968). Official congressional directory: For the use of the United States Congress ; closing date for compiling directory material, December 15, 1967. United States Government Printing Office.
Cita Chicago (17th ed.)US. Congress. Official Congressional Directory: For the Use of the United States Congress ; Closing Date for Compiling Directory Material, December 15, 1967. Washington: United States Government Printing Office, 1968.
Cita MLA (9th ed.)US. Congress. Official Congressional Directory: For the Use of the United States Congress ; Closing Date for Compiling Directory Material, December 15, 1967. United States Government Printing Office, 1968.
Atenció: Aquestes cites poden no estar 100% correctes.