Não informado. (2002). Journal of Transportation and Statistics. US Department of Transportation, Bureau of Transportation Statistics.
Citação do estilo Chicago (17ª ed.)Não informado. Journal of Transportation and Statistics. Washington: US Department of Transportation, Bureau of Transportation Statistics, 2002.
Citação MLA (8ª ed.)Não informado. Journal of Transportation and Statistics. US Department of Transportation, Bureau of Transportation Statistics, 2002.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.