“The Status of Micronutrients and Sulphur in Some Plantation Crops at Different Ages in an Alfisol of Southern Nigeria”. JOURNAL OF TROPICAL SOILS 19, no. 2 (April 20, 2015): 53–58. Accessed November 7, 2025. https://journal.unila.ac.id/index.php/tropicalsoil/article/view/201.