1. Allen WR: Practical control of anoestrus in Thoroughbred broodmares. In: Ellendorff F, Ellsaesser F (eds.): Endocrine causes of seasonal and lactational anestrus in farm animals. Martinus Nijhoff Publishers, Dordrecht, 1985, 98–107.
2. Arthur GH: An analysis of the reproductive function of mares based on post-mortem examination. Vet. Rec., 1958, 70, (682–686).
3. Dowsett KF, Knott LM, Woodward RA, Bodero DAV: Seasonal variation in the estrous cycle of mares in the subtropics. Theriogenology, 1993, 39, (631–653).
4. Dyrmundsson OR: Reproduction of Icelandic horses with special reference to seasonal sexual activity. Horse breeding and production in cold climatic regions, Reykjavik, Iceland, 11.-13.8.1993.
5. Ginther OJ: Occurrence of anestrus, estrus, diestrus, and ovulation over a 12-month period in mares. Amer. J. vet. Res., 1974, 35, (1173–1179).