Rizal, S., Utama, S., Utomo, B., Susilowati, S., Mulyati, S., Ismudiono, I. and Soeharsono, S. 2020. Interkorelasi antara persentase konsentrat, kadar urea nitrogen susu dan beberapa variabel sapi perah Friesian Holstein. Ovozoa: Journal of Animal Reproduction. 9, 2 (Aug. 2020), 53–59. DOI:https://doi.org/10.20473/ovz.v9i2.2020.53-59.