(1997). Highway safety design and operations guide 1997. Washington: American Association of State Highway and Transportation Officials.
Παραπομπή Chicago StyleHighway Safety Design and Operations Guide 1997. Washington: American Association of State Highway and Transportation Officials, 1997.
Παραπομπή MLAHighway Safety Design and Operations Guide 1997. Washington: American Association of State Highway and Transportation Officials, 1997.
Πρόσοχή: Οι παραπομπές μπορεί να μην είναι 100% ακριβείς.