American Association of State Highway and Transportation Officials. "Organization". American Association of State Highway and Transportation Officials. Archived from the original on April 4, 2016. Retrieved March 30, 2016.
American Association of State Highway and Transportation Officials. "Bookstore". American Association of State Highway and Transportation Officials. Retrieved March 30, 2016.
web.archive.org
American Association of State Highway and Transportation Officials. "Organization". American Association of State Highway and Transportation Officials. Archived from the original on April 4, 2016. Retrieved March 30, 2016.