Ahmad, J., H. Hanisah, and R. Rozalina. “WELFARE LEVEL OF RUBBER TAPPERS IN THE SUNGEI PUTIH RESEARCH UNIT, GALANG SUBDISTRICT, DELI SERDANG DISTRICT”. Jurnal Inovasi Penelitian, Vol. 4, no. 7, Dec. 2023, pp. 1259-66, doi:10.47492/jip.v4i7.2996.