Não informado. (1974). Directory. Transportation Research Board, National Research Council.
Chicago-referens (17:e uppl.)Não informado. Directory. Washington: Transportation Research Board, National Research Council, 1974.
MLA-referens (8:e uppl.)Não informado. Directory. Transportation Research Board, National Research Council, 1974.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.