Sebayang, L. . “ASSESSMENT OF COMMODITIES AREA GAMBIER (Uncaria Gambir Roxb.) IN PAKPAK BHARAT SCALE 1 : 50.000”. Jurnal Online PERTANIAN TROPIK, vol. 2, no. 2, Aug. 2015, pp. 102-109`, doi:10.32734/jpt.v2i2.2890.