United States Postal Service. (1994). 1994 [i.e. one thousand, nine hundred and ninety four] commemorative stamp collection. U.S. Postal Service.
Chicago Style (17th ed.) CitationUnited States Postal Service. 1994 [i.e. One Thousand, Nine Hundred and Ninety Four] Commemorative Stamp Collection. México: U.S. Postal Service, 1994.
MLA引文United States Postal Service. 1994 [i.e. One Thousand, Nine Hundred and Ninety Four] Commemorative Stamp Collection. U.S. Postal Service, 1994.
警告:这些引文格式不一定是100%准确.