APA-referens (7:e uppl.)

United States Postal Service. (1998). 1998 [i.e. one thousand, nine hundred and ninety eight] stamp yearbook. U.S. Postal Service.

Chicago-referens (17:e uppl.)

United States Postal Service. 1998 [i.e. One Thousand, Nine Hundred and Ninety Eight] Stamp Yearbook. España: U.S. Postal Service, 1998.

MLA-referens (8:e uppl.)

United States Postal Service. 1998 [i.e. One Thousand, Nine Hundred and Ninety Eight] Stamp Yearbook. U.S. Postal Service, 1998.