ALTERNATIF UPAYA PENANGGULANGAN KELANGKAAN PENYADAP DI PERUSAHAAN PERKEBUNAN KARET (THE EFFORT TO OVERCOME TAPPERS SCARCITY IN RUBBER ENTERPRISES). (2017). Inovasi, 14(2), 142-154. https://jurnal.sumutprov.go.id/index.php/inovasi/article/view/100