Wenzel , James G.W., Robert L. Carson, and Dwight F. Wolfe. 2012. “Bull-to-Cow Ratios: Practical Formulae for Estimating the Number of Bulls Suggested for Successful Pasture Breeding of Female Cattle”. Clinical Theriogenology 4 (4):477-79. https://clinicaltheriogenology.net/index.php/CT/article/view/13606.