Cunningham, W. P., & Cunningham, M. A. (2015). Environmental science: A global concern (Thirteenth edition.). McGraw-Hill Education.
Dyfyniad Arddull ChicagoCunningham, William P., and Mary Ann Cunningham. Environmental Science: A Global Concern. Thirteenth edition. New York, NY: McGraw-Hill Education, 2015.
Dyfyniad MLACunningham, William P., and Mary Ann Cunningham. Environmental Science: A Global Concern. Thirteenth edition. McGraw-Hill Education, 2015.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.