Não informado. (1968). Research Results Digest. National Cooperative Highway Research Program.
Chicagoスタイル(17版)引用形式Não informado. Research Results Digest. Washington: National Cooperative Highway Research Program, 1968.
MLA(8版)引用形式Não informado. Research Results Digest. National Cooperative Highway Research Program, 1968.
警告: この引用は必ずしも正確ではありません.