Allen, J. L. (1996). Environment 96/97. (15th ed.). Dushkin Publishing Group.
Cita Chicago (17th ed.)Allen, John L. Environment 96/97. 15th ed. Connecticut: Dushkin Publishing Group, 1996.
Cita MLA (9th ed.)Allen, John L. Environment 96/97. 15th ed. Dushkin Publishing Group, 1996.
Atenció: Aquestes cites poden no estar 100% correctes.