Abaye, A.O., Brann, D.E., Alley, M.M. and Griffey, C.A. (1997) Winter durum wheat: Do we have all the answers? Knowledge for the Common Wealth, Virginia State University, Publication No. 424-802.
 Pitz, W. (1992) Durum wheat/semolina/farina/pasta quality. North Dakota State University.
 D’Egidio, M.G. (2012) From seed to pasta in Ethiopia: Opportunities and challenges to overcome for smallholder farmers in Bale area. CRA Consiglio Perla Ricerca e la Sperimentazione in Agricolture, IAO.
 Gooding, M.J. and Devis, W.P. (1997) Wheat production and utilization. CAB International, Wallingford.
 Motozo, R., Fosi, S. and Giunta, F. (2004) Relationship between grain yield and quality of durum wheats from different eras of breeding. Euphytica, 140, 147-158.
 Franzen, D.W. and Goos, R.J. (1997) Fertilizing hard red spring wheat, durum, winter and rye. North Dakota State University Extension Service, SF-712.
 Tesemma, T. and Belay, G. (1991) Aspects of Ethiopian tetraploid wheats with emphasis on durum wheat genetics and breeding research. In: Gebre-Mariam, H., Tanner, D.G. and Hulluka, M., Eds., Wheat Research in Ethiopia: A Historical Perspective, IAR/CIMMYT, Addis Ababa, 47-71.
 Virman, S.M., Sahrawat, K.L. and Burford, J.R. (1982) Physical and chemical properties of vertisols and their management. 12th International Congress of Soil Science, 8-16 February 1982, New Delhi, 80-93.
 Sahrawat, K.L. (1980) Control of urea hydrolysis and nitrification in soil by chemicals—Prospects and problems. Plant and Soil, 57, 335-352. doi:10.1007/BF02211691
 Terman, G.L. (1979) Volatilization losses of nitrogen as ammonia from surface-applied fertilizers, organic amendments, and crop residues. Advances in Agronomy, 31, 189-223. doi:10.1016/S0065-2113(08)60140-6
 Impiglia, A. and Anderson, W. (1998) Essentials of a successful durum wheat crop. Agriculture Western Australia.
 Russell, R.S. (1977) Plant root systems: Their function and interaction with the soil. McGraw Hill Co., London, 277.
 Sigunga, D.O., Janssen, B.H. and Oenema, O. (2002) Denitrification risks in relation to fertilizer Nitrogen losses from vertisols and phaoezems. Communications in Soil Science and Plant Analysis, 33, 561-578.
 Geleto, T., Tanner, D.G., Mamo, T. and Gebeyehu, G. (1996) Response of rainfed bread and durum wheat to source, level and timing of nitrogen fertilizer on two Ethiopian vertisols: II. N uptake, recovery and efficiency. Fertilizer Research, 44, 195-204.
 Gashawbeza, B., Yaekob, A., Zemede, A., Kifetew, J. and Tadesse, T. (2003) Fertilizer N effects on yield and grain quality of durum wheat. Tropical Agriculture (Trinidad), 80, 146-151.
 Hadjichristoudoulou, A. (1979) Genetic and environmental effects of vitreousness of durum wheat. Euphytica, 28, 711-716. doi:10.1007/BF00038938
 Ethiopian Agricultural Research Organization (EARO) (2004) Directory of released crop varieties and their recommended cultural practices. EARO, Addis Ababa.
 Erokossa, T., Karl, S. and Thomas, G. (2006) Soil tillage and crop productivity on a vertisols in Ethiopian highlands. Soil Tillage Research, 85, 200-211.
 Chaney, K. (1990) Effects of nitrogen fertilizer rate on soil nitrate nitrogen content after harvesting winter wheat. Journal of Agricultural Science, Cambridge, 114, 171- 176.
 Campbell, C.A., Myers, R.J.K. and Curtin, D. (1995) Managing nitrogen for sustainable crop production. Fertilizer Research, 42, 277-296. doi:10.1007/BF00750521
 Nelson, D.W. and Sommers, L.E. (1982) Total carbon and organic matter. In: Page, A.L., et al., Eds., Methods of Soil Analysis Part 2: Chemical and Microbial Properties, 2nd Edition, Amer Society of Agronomy, Madison, 539- 579.
 Walkley, A. and Black, I.A. (1934) An examination of the Degtjareff method for determining soil organic matter and proposed modification of the chromic acid titration method. Soil Science, 37, 29-38.
 IITA (1979) Selected methods for soil and plant analysis. IITA (International Institute of Tropical Agriculture). Manual Series No. 1, Ibadan.
 Page, A.L., Miller, R.H. and Keeny, D.R. (1982) Methods of soil analysis II. Chemical and micro biological properties. No. 9 in the series of agronomy Inc. Soil Science Society of America, Inc., Madison.
 Yerima, B.P.K. (1993) Manual for good laboratory practice. Food and Agriculture Organization of the United Nation, Addis Ababa.
 Olsen, S.R., Cole, C.V., Wantanabe, F.S. and Dean, L.A. (1954) Estimation of available phosphorus in soils by extraction with sodium bicarbonate. Circular (US Department of Agriculture), 939, 19 p.
 Houba, V.J.G., Vander Lee, J.J., Novozamsky, I. and Waligna, I. (1989) Soil and plant analysis a series of syllabi. Part 5: Soil analysis procedures. Wageningen Agricultural University, Wageningen, The Netherlands.
 Caldicott, J.J.B. and Nuttal, A.M. (1979) A method for the assessment of lodging in cereals crops. Journal of the National Institute of Agricultural Botany, 15, 88-91.
 International Association for Cereal Science and Technology (ICC) (2000) Standard methods of international association for cereal science and technology. ICC, Vienna.
 SAS Institute (2000) SAS/STAT user’s guide: Version 7. SAS Institute Inc., Cary.
 Ames, N.P., Clarke, J.M., Dexter, J.E., Woods, S.M., Selles, F. and Marchylo, B. (2003) Effects of nitrogen fertilizer on protein quantity and gluten strength parameters in durum wheat (Triticum turgidum L. var. durum) cultivars of variable Gluten strength. Cereal Chemistry, 80, 203-211. doi:10.1094/CCHEM.2003.80.2.203
 Metho, A.L., Hammes, P.S. and De Beer, J.M. (1997) Effect of cultivars and soil fertility on grain yield, yield components and grain nitrogen content of wheat. African Crop Science Journal, 3, 695-709.
 Simmonds, D.H. (1989) Inherent quality factors in wheat. Wheat and Wheat Quality in Australia, CSIRO, 31-61.
 Srivastava, J.P. (1984) Durum wheatits world status and potential in the Middle East and North Africa. Rachis (Barley and Wheat Newsletter), 3, 1-8.
 Campbell, C.A., Davidson, H.R. and Warder, F.G. (1977) Effects of fertilizer N and soil moisture on yield, yield components, protein content and N accumulation in the above ground parts of spring wheat. Canadian Journal of Soil Science, 57, 311-327. doi:10.4141/cjss77-036
 Yamazaki, W.T. and Briggle, L.W. (1969) Components of test weight in soft wheats. Crop Science, 9, 457-460.
 Budak, N. (2000) Heritability, correlation and genotype x year interactions of grain yield, test weight and protein content in durum wheats. Turkish Journal of Field Crops, 5, 35-40.
 Troccoli, A. and di Fonzo, N. (1999) Relationship between kernel size features and test weight in Triticum durum. Cereal Chemistry, 76, 45-49.
 Stoskopf, N.C. (1985) Cereal grain crops. Reston Publishing Company, Inc., Reston.