APA-čujuhus (7. p.)
United States Postal Service. History of the United States Postal Service: 1775-1993.
Chicago-čujuhus (17. p.)
United States Postal Service. History of the United States Postal Service: 1775-1993.
MLA-čujuhus (9. p.)
United States Postal Service. History of the United States Postal Service: 1775-1993.
Muitte dárkkistit čujuhemiid riektatvuođa, ovdal go geavahat daid iežat deavsttas.