Siburian, E. ., and L. A. Siregar. “Various Natural Ingredients As Plant Growth Regulator to Increasing Viability True Seed Shallot of Onion”. Jurnal Online Pertanian Tropik, vol. 6, no. 1, Dec. 2019, pp. 80-87, doi:10.32734/jopt.v6i1.3043.