Irawan, Bambang. 2015. “Soil Properties and the Abundace of Ironwood (Eusideroxylon Zwageri Teijsm.& Binn.) Varieties in Jambi, Indonesia”. Jurnal Manajemen Hutan Tropika 21 (3). Bogor, INA, 155-61. https://journal.ipb.ac.id/index.php/jmht/article/view/10797.