Söderström, Mats, Christian Isendahl, Jan Eriksson, Suzana Romeiro Araújo, Lilian Rebellato, Denise Pahl Schaan, and Per Stenborg. “Using Proximal Soil Sensors and Fuzzy Classification for Mapping Amazonian Dark Earths”. Agricultural and Food Science 22, no. 4 (December 18, 2013): 380–389. Accessed March 28, 2024. https://journal.fi/afs/article/view/8195.