United States Postal Service. (1993). 1993 [i.e. one thousand, nine hundred and ninety three] commemorative stamp collection. U.S. Postal Service.
Citación estilo ChicagoUnited States Postal Service. 1993 [i.e. One Thousand, Nine Hundred and Ninety Three] Commemorative Stamp Collection. México: U.S. Postal Service, 1993.
Cita MLAUnited States Postal Service. 1993 [i.e. One Thousand, Nine Hundred and Ninety Three] Commemorative Stamp Collection. U.S. Postal Service, 1993.
Warning: These citations may not always be 100% accurate.