Não informado. (2002). Journal of Transportation and Statistics. US Department of Transportation, Bureau of Transportation Statistics.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. Journal of Transportation and Statistics. Washington: US Department of Transportation, Bureau of Transportation Statistics, 2002.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. Journal of Transportation and Statistics. US Department of Transportation, Bureau of Transportation Statistics, 2002.
Πρόσοχή: Οι παραπομπές μπορεί να μην είναι 100% ακριβείς.