NURSYAMSI, D. Effect of Oxalic Acid, Na+, NH4+, and Fe3+ on Release of Fixed Potassium and Basal Distance of Smectite in Smectitic Soils. JOURNAL OF TROPICAL SOILS, [S. l.], v. 14, n. 3, p. 177–184, 2009. DOI: 10.5400/jts.2009.v14i3.177-184. Disponível em: https://journal.unila.ac.id/index.php/tropicalsoil/article/view/84. Acesso em: 1 aug. 2025.