Nainggolan, Hotden, Johndikson Aritonang, Marlon Sihombing, Tavi Supriana, and Ma’ruf Tafsin. 2019. “Structural Modelling of Rice Fields-Buffalo Livestock Based Integrated Agricultural Systems in the Context of Regional Development in Humbang Hasundutan, Indonesia”. Future of Food: Journal on Food, Agriculture and Society 7 (2), Article Nr. 106. https://www.thefutureoffoodjournal.com/index.php/FOFJ/article/view/251.