1. Crandall, C. S. (1924). “Additional records of self-sterility in apples.”Proc. Amer. Soc. Hort. Sci. p. 63.
2. Crane, M. B. (1921). “Experiments in breeding plums.”Journ. Pomol. 2, 137.
3. —— (1926). “Self- and cross-sterility in fruit trees. A summary of results, 1911–25.” Ibid.6, 157.
4. —— (1931). “Fertility in relation to yield in cultivated fruits.”Fac. of Agric., Univ. of Reading, Bull. 41, 119.
5. Crane, M. B. andLawrence, W. J. C. (1929). “Genetical and cytological aspects of incompatibility and sterility in cultivated fruits.”Journ. Pomol. Hort. Sc. 7, 276.