Não informado. (1974). Directory. Transportation Research Board, National Research Council.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. Directory. Washington: Transportation Research Board, National Research Council, 1974.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. Directory. Transportation Research Board, National Research Council, 1974.
Πρόσοχή: Οι παραπομπές μπορεί να μην είναι 100% ακριβείς.