Root Kustritz , M. V., M. R. Slater, G. R. Weedon, and P. A. Bushby. “Determining Optimal Age For Gonadectomy In The Dog: A Critical Review Of The Literature To Guide Decision Making”. Clinical Theriogenology, vol. 9, no. 2, June 2017, pp. 167-11, https://clinicaltheriogenology.net/index.php/CT/article/view/10074.