ThanhN. V., HangP. T., GioiP. V., ToanN. C., and LongS. T., “The Relationship Between Plasma Progesterone Concentration on Day 6 After Artificial Insemination and Pregnancy Rate of Dairy Cows in Vietnam”, Trop. Anim. Sci. J., vol. 46, no. 2, pp. 146-150, May 2023.