1. Correns, C. (1912). “Selbststerilität und Iudividualstoffe.”Festschr. d. med.-naturwiss. Ges. z. 84Versamml. deutsch. Naturforscher u. Ärzte 1912, Münster-i.-W.
2. Crane, M. B. andLawrence, W. J. C. (1920). “Genetical and cytological aspects of incompatibility and sterility in cultivated fruits,”Journ. Pom. and Hort. Sci. vii, No. 4, pp. 276–301.
3. — (1030). “Fertility and vigour of apples in relation to chromosome number.”Journ. Gen. xxii, 153–63.
4. Darlington, C. D. (1928). “Studies inPrunus, I and II.”Ibid. xix, 213–56.
5. — (1930). “Studies inPrunus, III.”Ibid. xxii, 65–93.