Pfafflin, J. R., & Ziegler, E. N. (1998). Encyclopedia of Environmental Science and Engineering (4th ed., Revised and updated.). Gordon And Breach Science Publishers.
Dyfyniad Arddull ChicagoPfafflin, James R., and Edward N. Ziegler. Encyclopedia of Environmental Science and Engineering. 4th ed., Revised and updated. Australia: Gordon And Breach Science Publishers, 1998.
Dyfyniad MLAPfafflin, James R., and Edward N. Ziegler. Encyclopedia of Environmental Science and Engineering. 4th ed., Revised and updated. Gordon And Breach Science Publishers, 1998.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.