1. CSA (Central Statistics Agency) (2014) Agricultural Sample Survey 2013/2014 Volume I. Report on Area and Production of Major Crops (Privet Peasant Holdings, Meher Season). Statistical Bulletin 532, Addis Ababa.
2. Maximizing Net Returns to Financially Constrained Fertilizer Use
3. Fertilizer use optimization: principles and approach.
4. Kaizzi, K.C., Wortmann, C.S. and Jansen, J.A. (2013) More Profitable Fertilizer Use for Poor Farmers. Better Crops, 97, 4-6.
5. Hydrometer Method Improved for Making Particle Size Analyses of Soils
1