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