Two culture systems showing a biphasic effect on ovine embryo development from the 1-2 cell stage to hatched blastocysts S. Ledda, L. Bogliolo, G. Leoni, P. Loi, P. Cappai and S. Naitana Reprod. Nutr. Dev., 35 6 (1995) 629-637 DOI: 10.1051/rnd:19950603