Não informado. (1931). Highway research abstracts. National Research Council, Highway Research Board.
Citação do estilo Chicago (17ª ed.)Não informado. Highway Research Abstracts. Washington: National Research Council, Highway Research Board, 1931.
Citação MLA (8ª ed.)Não informado. Highway Research Abstracts. National Research Council, Highway Research Board, 1931.
Atenció: Aquestes cites poden no estar 100% correctes.