(1968). United States government correspondence manual. U.S. Government Printing Office.
Citazione stile Chigago Style (17a edizione)United States Government Correspondence Manual. Washington: U.S. Government Printing Office, 1968.
Citatione MLA (9a ed.)United States Government Correspondence Manual. U.S. Government Printing Office, 1968.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.