Não informado. Transportation: Current literature. U.S. Department of Transportation.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. Transportation: Current Literature. Washington: U.S. Department of Transportation.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. Transportation: Current Literature. U.S. Department of Transportation.
Πρόσοχή: Οι παραπομπές μπορεί να μην είναι 100% ακριβείς.