Não informado. (1966). Summary of progress. National Cooperative Highway Research Program.
Chicago-referens (17:e uppl.)Não informado. Summary of Progress. Washington: National Cooperative Highway Research Program, 1966.
MLA-referens (8:e uppl.)Não informado. Summary of Progress. National Cooperative Highway Research Program, 1966.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.