Biogas Production from Palm Oil Fruit Bunch in Anaerobic Biodigester through Liquid State (LS-AD) and Solid State (SS-AD) MethodBakti Jos, Hanif Farhan, Nadia Dwi Ayu, Budiyono and Siswo SumardionoMATEC Web Conf., 156 (2018) 03043DOI: https://doi.org/10.1051/matecconf/201815603043