SamsuriS., JayaI. N. S., KusmanaC., and MurtilaksonoK. “Tropical Forest Landscape Fragmentation in Batang Toru Watershed, North Sumatra”. Jurnal Manajemen Hutan Tropika, Vol. 20, no. 2, Sept. 2014, pp. 77-85, https://journal.ipb.ac.id/index.php/jmht/article/view/8439.