Não informado. (1926). General contracting. Engineering and Contracting Publishing.
Chicago-referens (17:e uppl.)Não informado. General Contracting. Chicago, Ill: Engineering and Contracting Publishing, 1926.
MLA-referens (8:e uppl.)Não informado. General Contracting. Engineering and Contracting Publishing, 1926.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.