1. Allen , W. Edward 1973 A Clinical and Endocrinological Study of Reproduction in the Mare Ph.D. thesis
2. Ovarian changes during gestation in pony mares;Allen;Equine vet. J.,1974a
3. Palpable development of the conceptus and foetus in Welsh pony mares;Allen;Equine vet. J.,1974b
4. Allen , W. Edward Hadley , J. C. 1972 Daily blood progesterone concentrations during the oestrous cycle compared with those of early pregnancy and embryonic resorption in mares. VIIth Intern. Cong. Anim. Reprod. and A.I., Munich II, 1189-1193
5. The origin of equine endometrial cups: II Invasion of the endometrium by trophoblast;Allen;Anat. Rec.,1973