Suhartana, I Putu Gde, et al. “The Study of Cow Manure Sludge Fermentation Process”. Jurnal BETA (Biosistem Dan Teknik Pertanian), vol. 5, no. 1, Feb. 2026, pp. 51-60, doi:10.24843/JBETA.2017.v05.i01.p07.