(Firm), P. (1997). The Guide to graduate environmental programs. Washington, D.C.
Chicago Style Citation(Firm), ProQuest. The Guide to Graduate Environmental Programs. Washington, D.C, 1997.
MLA引文(Firm), ProQuest. The Guide to Graduate Environmental Programs. Washington, D.C, 1997.
警告：這些引文格式不一定是100％准確.