Não informado. (1974). American Highway and Transportation Magazine. American Association of State Highway and Transportation Officials.
Citação do estilo Chicago (17ª ed.)Não informado. American Highway and Transportation Magazine. Washington: American Association of State Highway and Transportation Officials, 1974.
Citação MLA (8ª ed.)Não informado. American Highway and Transportation Magazine. American Association of State Highway and Transportation Officials, 1974.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.