Johnson, G. B. (2006). The living world. Boston, MA: McGraw-Hill.
Dyfyniad Arddull ChicagoJohnson, George Brooks. The Living World. Boston, MA: McGraw-Hill, 2006.
Dyfyniad MLAJohnson, George Brooks. The Living World. Boston, MA: McGraw-Hill, 2006.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.