Khampa, Sittisak, et al. “Supplementation of Malate Level and Cassava Hay in High-Quality Feed Block on Ruminal Fermentation Efficiency and Digestibility of Nutrients in Lactating Dairy Cows”. Pakistan Journal of Nutrition, vol. 8, no. 4, Mar. 2009, pp. 441–446, https://doi.org/10.3923/pjn.2009.441.446.