Tjiptosumirat, Totti, et al. “REPRODUCTIVE DISORDER STUDIES USING RADIOIMMUNOASSAY (RIA) PROGESTERONE ON DAIRY CATTLE”. Jurnal Ilmiah Aplikasi Isotop Dan Radiasi, vol. 2, no. 1, Sept. 2013, pp. 30-49, doi:10.17146/jair.2006.2.1.563.