1. Darwin , C. 1868.The variation of animals and plants under domesticationVol. 2, 91–91. N.Y. 2 vols.
2. Stern , C. and Sherwood , E.R. 1966.The origin of geneticsx–x. San Francisco and London
3. Stern and Sherwood . 1966.The origin of genetics134–134. San Francisco and London note 1