“Rekomendasi Pemupukan NPK pada Tanaman Kakao (Theobroma Cacao) di Desa Metun Sajau Kecamatan Tanjung Palas Timur, Kabupaten Bulungan, Provinsi Kalimantan Utara: Recommendations For NPK Fertilization on Cocoa (Theobroma Cacao) Plants in Metun Sajau Village, East Tanjung Palas Sub-District, Bulungan District, North Kalimantan Province” (2022) Jurnal Ecosolum, 11(2), pp. 126–135. doi:10.20956/ecosolum.v11i2.23487.