Arief, N. Jamarun, and B. Satria, “Characteristics of Ettawa Crossbred Dairy Goat Rumen Fluid and Digestibility of Palm Oil Industry By-Products”, Pak. J. Nutr., vol. 15, no. 1, pp. 28–32, Dec. 2015, doi: 10.3923/pjn.2016.28.32.