Purves, W. K., & Orians,Gordon H. (1987). Life: The science of biology (2nd ed.). Sinauer.
Dyfyniad Arddull ChicagoPurves, William K., and Orians,Gordon H. Life: The Science of Biology. 2nd ed. Massachusetts: Sinauer, 1987.
Dyfyniad MLAPurves, William K., and Orians,Gordon H. Life: The Science of Biology. 2nd ed. Sinauer, 1987.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.