Klug, William S.; Michael R. Cummings; Charlotte A. Spencer (2006). Concepts of Genetics. Upper Saddle River, NJ: Pearson Education Inc. p. 215. ISBN9780131918337.
Klug, William S.; Michael R. Cummings; Charlotte A. Spencer (2006). Concepts of Genetics. Upper Saddle River, NJ: Pearson Education Inc. p. 223. ISBN9780131918337.