Não informado. (2004). Highway research circular. National Research Council, Highway Research Board.
Chicago-referens (17:e uppl.)Não informado. Highway Research Circular. Washington: National Research Council, Highway Research Board, 2004.
MLA-referens (8:e uppl.)Não informado. Highway Research Circular. National Research Council, Highway Research Board, 2004.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.