7Hamra A H, Massri Y G, Marcek J M, et al. Plasma progesterone levels in ewes treated with progesterone controlled internal dreg release dispensers, implets and sponges[J]. Anita Reprod Sic, 1986, 11: 187-194.
8Naqvi S M K, Gulyani R. The effect of gonadotrophin releasing hormone and follicle stimulating hormone in conjunction with pregnant mareserum gonadotrophin on the superovulatory response in crossbred sheep in india[J]. Trop Anim Health Pro, 1998, 30: 369-376.
9Moore N W. The control of oestrous, ovulation and fertility in relalion to artificial insemination in the Angora goat[J]. J Agric Res, 1979, 30:965-972.
10Robinson J J, Fraser C, Mc Hattie I. The use of progestagens and photoperidisim in improving the reprodactiv rate of the ewe [J]. Ann Bio Anim Bioch Biophy, 1975, 15: 345-352.