Cunningham, W. P., & Cunningham, M. A. (2004). Principles of environmental science: Inquiry and applications (2nd ed.). Boston: McGraw-Hill Higher Education.
Dyfyniad Arddull ChicagoCunningham, William P., và Mary Ann Cunningham. Principles of Environmental Science: Inquiry and Applications. 2nd ed. Boston: McGraw-Hill Higher Education, 2004.
Dyfyniad MLACunningham, William P., và Mary Ann Cunningham. Principles of Environmental Science: Inquiry and Applications. 2nd ed. Boston: McGraw-Hill Higher Education, 2004.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.