Simatupang, R. Smith, and L. Indrayati. “Pengarub Pemberian Kompos Gulma Somber Hara NPK Terbadap Tanaman Padi Di Laban Sulfat Masam”. Jurnal Agronomi Indonesia (Indonesian Journal of Agronomy), vol. 31, no. 2, Aug. 2003, https://doi.org/10.24831/jai.v31i2.1464.