Sarker, MSK, et al. “Effect of Genotype and Lactation on Milk Urea Nitrogen, Blood Urea Nitrogen and Milk Composition of Dairy Cows”. Bangladesh Journal of Livestock Research, vol. 19, no. 1-2, Jan. 2016, pp. 74-84, doi:10.3329/bjlr.v19i1-2.26429.