BudiansyahA., ResmiR., FilawatiF., and HaroenU. “Performance of Kerinci Ducks Treated by Cattle Rumen-Fluid Supernatant Addition As Source of Crude Enzyme in Rations”. Tropical Animal Science Journal, Vol. 43, no. 2, June 2020, pp. 125-32, doi:10.5398/tasj.2020.43.2.125.