Irawan, D., Nugrahini, T., & Mahdalena. (2013). Effect of Fertilizer Manure on Growth Swallow Seed Varieties Some Rubber (Hevea brasiliensis Muell Arg): Pengaruh Pemberian Pupuk Kotoran Burung Walet Terhadap Pertumbuhan Beberapa Varietas Bibit Karet (Hevea brasiliensis Muell Arg. Agrifarm: Jurnal Ilmu Pertanian, 2(1), 7–10. Retrieved from https://journal.uwgm.ac.id/agrifarm/article/view/1248