Dyfyniad APA
Pilkey, O. H., & Pilkey-Jarvis, L. (2007). Useless arithmetic: Why environmental scientists can't predict the future. Columbia University Press.
Dyfyniad Arddull Chicago
Pilkey, Orrin H., and Linda Pilkey-Jarvis. Useless Arithmetic: Why Environmental Scientists Can't Predict the Future. New York: Columbia University Press, 2007.
Dyfyniad MLA
Pilkey, Orrin H., and Linda Pilkey-Jarvis. Useless Arithmetic: Why Environmental Scientists Can't Predict the Future. Columbia University Press, 2007.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.