1. R. A. Fisher, Statistical Methods for Research Workers. ( Oliver & Boyd, Edinburgh, 1925 ).
2. “Student”: On Testing Parities of Cereals. (Biometrika. XV, pp. 271–293, 1923.)
3. Sir John Russell: Field Experiments: How They are Made and What They are. (Jour. Min. Agric.. XXXII. 1926, pp. 989–1001.)