1. Austin CR, Bishop JWH. 1958. Proc. Roy. Soc. B. 149, 241–248.
2. Adams CE, Chang MC. 1962. J. Exp. Zool. 188, 203–210.
3. Bedford JM. 1968. Am. J. Anat. 123, 329–358.
4. Bedford JM. 1969. J. Reprod. Fert. Suppl. 8, 19–26.
5. Bedford JM. 1982. In Reproductive in Mammals, Vol. 1. Gametes and Fertilization, 2nd Eds Austin, C.R. Short R.V., Camb. Univ. Press In press.