Não informado. (1966). Summary of progress. National Cooperative Highway Research Program.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. Summary of Progress. Washington: National Cooperative Highway Research Program, 1966.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. Summary of Progress. National Cooperative Highway Research Program, 1966.
Πρόσοχή: Οι παραπομπές μπορεί να μην είναι 100% ακριβείς.
