Kakkar, V. K., S. R. Marwaha, and A. K. Chopra. “Distillation of Volatile Fatty Acids in the Rumen Liquor”. The Indian Journal of Nutrition and Dietetics, vol. 8, no. 6, Nov. 1971, pp. 329-32, http://informaticsjournals.com/index.php/ijnd/article/view/11289.