Ambrosia , R., R. Gilbert, D. Bergfelt, J. Samper, E. Peterson, and H. French. “Sample Handling Has Minimal Effect on Blood Progesterone Concentrations in Jennies”. Clinical Theriogenology, vol. 12, no. 2, 1, pp. 121-3, doi:10.58292/ct.v12i2.9207.