Coste, R. (1992) Coffee: The plant and the product. Macmillan, London.
 Wintgens, J.N. (2004) Coffee: Growing, processing, sustainable production. A guide for growers, traders, and researchers. WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim.
 Wrigley, G (1988) Coffee. Tropical Agriculture Series, John Wiley and Sons, Inc., London.
 Paulos, D. (1994) Mineral fertilization of coffee in Ethio- pia. Institute of Agricultural Research, Addis Ababa.
 Cambrony, H.R. (1992) Coffee growing. CTA/The Macmillan Press Ltd., New York.
 Francis, B., Taye, K., Shalander, K., Julious, O., Efrain, A.P. and Africa, Z. (2000) Natural resources under threat: An analysis of the farming systems of ghimbo wereda, Kefa-Sheka Zone, Ethiopia. ICRA Working Document Series 84, Wageningen.
 Paulos, D. and Demel, T. (2000) The need for forest coffee germplasm conservation in Ethiopia and its significance in the control of coffee diseases. Proceedings of the workshop on control of Coffee Berry Disease (CBD) in Ethiopia, Addis Ababa, 13-15 August 1999, 125-135.
 Tadesse, W., Denich, M., Demel, T. and Vlek, P.L.G. (2001) Human impacts on Coffea arabica genetic pools in Ethiopia and the need for its in situ conservation. In: Rao, R., Brown, A. and Jackson, M., Eds., Managing Plant Genetic Diversity, CABI and IPGRI, 237-247.
 Tadesse, W. (2003) Vegetation of Yayu forest in SW Ethiopia: Impacts of human use and implications for in situ conservation of wild Coffea arabica L. populations. Ph.D. Thesis, Ecology and Development Series, No.10, Cuvillier Verlag, G?ttingen.
 Okalebo, J.R., Gathua, K.W. and Wormer, P.L. (1993) Laboratory methods of soil and plant analysis: A working manual. Soil Science Society of East Africa Technical Publication No 1, Marvel EPZ (Kenya) LTD, Nairobi.
 Tekalign, T., Haque, I. and Aduayi, E.A. (1991) Soil, plant, water, fertilizer, animal manure and compost analysis manual. Plant Science Division Working Document 13, ILCA, Addis Ababa.
 Murphy, H.L. (1968) A report on the fertility status and other data on some soils of Ethiopia. College of Agriculture, Haile Sellassie I University, Addis Ababa.
 Mesfin, A. (1998) Nature and management of Ethiopian soils. Alemaya University of Agriculture, ILRI, Addis Ababa.
 Brady, N.C. and Weil, R.R. (2002) The nature and properties of soils. 13th Edition, Pearson Education, Inc., Upper Saddle River.
 Brady, N. (1990) The nature and properties of soils. 10th Edition, Macmillan Publishing Company, Cranbury.
 Tewoldeberhan, G.E. (1986) Preliminary studies on the ecology of a natural coffee (Coffea arabica) forest with emphasis on coffee. Acta Universitatis Upsaliensis Symbolae Botanicae Upsalienses, 26, 146-156.
 Hofner, W. and Schmitz, M. (1984) Report on the soil and foliar analysis in 15 CIP areas in socialist Ethiopia. EEC/MCTD, Addis Ababa, Ethiopia.
 Paulos, D. and Moorby, J. (1995) Growth response of coffee (Coffea arabica L.) seedlings to phosphorus nutrition in nutrient solution. Proceedings of the 16th International Conference on Coffee Science (ASIC) Colloquium, Kyoto, 755-764.
 Franco, A.A. and Munns, D.N. (1982) Plant assimilation and nitrogen cycling. Plant and Soil, 67, 1-13.
 Hsieh, S.C. and Hsieh, C.F. (1990) The use of organic matter in crop production food and fertilizer technology center. Extension Bulletin, 315, Taiwan.
 FAO/UNESCO (1973) Soil map of the world. 6, UNESCO, Paris.
 Workafes, W.T. and Kassu, K. (2000) Coffee production systems in Ethiopia. Proceedings of the Workshop on the Control of Coffee Berry Disease (CBD) in Ethiopia, Addis Ababa (Ghion Hotel), 13-15 August 1999, 99-106.
 Feyera, S. (2006) Biodiversity and ecology of Afromon- tane rainforests with Coffea arabica L. populations in Ethiopia. Ph.D. Thesis, Ecology and Development Series No. 38, Cuvillier Verlag, G?ttingen.
 Taye, K. (2006) Ecophysiological diversity of wild Arabica coffee populations in Ethiopia: Growth, water relations and hydraulic characteristics along a climatic gradient. Ph.D. Thesis, Ecology and Development Series 46, Cuvillier Verlag, G?ttingen.
 Taye, K. and Tesfaye, S. (2002) Organic coffee production: Hope for small-scale farmers in Ethiopia. Proceedings of the 19th International Conference on Coffee Science (ASIC), Trieste, 14-18 May 2001.
 Taye, K. (2010) Environmental sustainability and coffee diversity in Africa. ICO World Coffee Conference, Guatemala City, 26-28 February 2010.