Não informado. (2004). Highway research circular. National Research Council, Highway Research Board.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. Highway Research Circular. Washington: National Research Council, Highway Research Board, 2004.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. Highway Research Circular. National Research Council, Highway Research Board, 2004.
Πρόσοχή: Οι παραπομπές μπορεί να μην είναι 100% ακριβείς.