Philippines. Bureau of Posts. Planning Division. (1977). Post office classification study. The Bureau.
Chicago-referens (17:e uppl.)Philippines. Bureau of Posts. Planning Division. Post Office Classification Study. [Manila]: The Bureau, 1977.
MLA-referens (9:e uppl.)Philippines. Bureau of Posts. Planning Division. Post Office Classification Study. The Bureau, 1977.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.