United States Postal Service. (1994). 1994 [i.e. one thousand, nine hundred and ninety four] commemorative stamp collection. U.S. Postal Service.
Citação do estilo Chicago (17ª ed.)United States Postal Service. 1994 [i.e. One Thousand, Nine Hundred and Ninety Four] Commemorative Stamp Collection. México: U.S. Postal Service, 1994.
Citação MLA (8ª ed.)United States Postal Service. 1994 [i.e. One Thousand, Nine Hundred and Ninety Four] Commemorative Stamp Collection. U.S. Postal Service, 1994.
Nota: a formatação da citação pode não corresponder 100% ao definido pela respectiva norma.