PUSPITA SARI, N.; IMAN SANTOSO, T.; MAWARDI, S. Distribution of Soil Fertility of Smallholding Arabica Coffee Farms at Ijen-Raung Highland Areas Based on Altitude and Shade Trees. Pelita Perkebunan (a Coffee and Cocoa Research Journal), v. 29, n. 2, 31 ago. 2013.