Simpkins, J., & Williams, J. I. (1989). Advanced biology (3rd ed.). Unwin Hyman.
Dyfyniad Arddull ChicagoSimpkins, J., and J. I. Williams. Advanced Biology. 3rd ed. London: Unwin Hyman, 1989.
Dyfyniad MLASimpkins, J., and J. I. Williams. Advanced Biology. 3rd ed. Unwin Hyman, 1989.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.