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.
Citazione stile Chigago Style (17a edizione)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.
Citatione MLA (9a 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.
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