Não informado. (1957). American road builder. American Road Builders Association.
Chicago-referens (17:e uppl.)Não informado. American Road Builder. Washington: American Road Builders Association, 1957.
MLA-referens (8:e uppl.)Não informado. American Road Builder. American Road Builders Association, 1957.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.