1. Bilton R.J. & Moore N.W. J. Reprod. Pert. 50, 363 (1977).
2. Whittingham D.J. Genetics 78, 395 (1974).
3. Blandau R.J. & Odor D.L. in Oogenesis (ed. Biggers & Schultz) 496, University Park Press, Baltimore/Butterworths, London, 1974.
4. Steinberger A. & Steinberger E. in Methods in Mammalian Embryology (ed. Daniel) Freeman & Co, San Francisco, 1977.
5. Hafez E.E. ibid.