Estrus, ovulation, and serum progesterone, estradiol, and LH concentrations in mares after an increased photoperiod during winter. February 1977 in “ PubMed ” Oxender Wd, Noden Pa, Hafs Hd We don't know much about this study yet. We're maintaining the world's largest resposity of hair loss research. You can help out the community by sending a PDF of this study here . Not sure how to get a study's PDF? You can email the authors of the study. View this study on pubmed.ncbi.nlm.nih.gov →