1. Riley, R., in Cytogenetics and the Evolution of Wheat (edit. by J. B. Hutchinson), 103 (Cambridge University Press, Cambridge, 1965).
2. Sears, E. R., Res. Bull. Mo. Agr. Exp. Sta., No. 572 (1954).
3. Kempanna, C., thesis, Univ. Cambridge (1963).
4. Riley, R., and Law, C. N., Adv. Genet., 13, 57 (1965).
5. Riley, R., and Chapman, V., Nature, 182, 713 (1958).