Witheford, D. K. (1999). Consultants for DOT preconstruction engineering work. National Academy Press.
Cita Chicago (17th ed.)Witheford, David K. Consultants for DOT Preconstruction Engineering Work. Washington, D.C: National Academy Press, 1999.
Cita MLA (9th ed.)Witheford, David K. Consultants for DOT Preconstruction Engineering Work. National Academy Press, 1999.
Atenció: Aquestes cites poden no estar 100% correctes.