Harahap, R. P., et al. “Enteric Methane Emissions and Rumen Fermentation Profile Treated by Dietary Chitosan: A Meta-Analysis of In Vitro Experiments”. Tropical Animal Science Journal, vol. 43, no. 3, Sept. 2020, pp. 233-9, https://doi.org/10.5398/tasj.2020.43.3.233.