Nuryanto, E. and Gouw, E. (2017) “ANALYSIS OF MACRONUTRIENS CONTENTS IN SOIL WITH NEAR INFRA RED (NIR) SPECTROSCOPY”, Jurnal Penelitian Kelapa Sawit, 25(2), pp. 85-94. doi: 10.22302/iopri.jur.jpks.v25i2.27.