7B Stroud, H Callesen. lETS statement on worldwide ET statistics for 2010[J]. Anita Reprod, 2012,9(3):210 -216.
8Hizli Hatiee ,Ayasan Tugay Gok, Kurtulus,et al. The Determination of Relationship Between Age and the Quality of Embryo of Donor Cows [J]. Kafkas Universi- tesi Veteriner Fakultesi Dergisi, 2011,17 (3) : 493-497.
9Mapletoft, Reuben J, Bo Gabriel A. The evolution of improved and simplified superovulation protocols in cattle [J]. Reproduction Fertility and Development, 2012, 24 (1) :278283.
10Marcelo F,Gouveia Nogueira, Breno J P. et al. Embryo recovery and pregnancy rates after the delay of ovulation and fixed time insemination in superstimulated beef cows [J]. Theriogenology,2002(57) : 1625-1634.
