1. Ayvaz, I., 1985.Gediz havzasi Alluviyal topraklarinin organic karbon, azot, fosfor ve kükürt içerigi üzerinde araştirmalar. Ege Uni. Zir. Fak. Toprak Bölümü, Doktora tezi.
2. Ammonium fixation and availability in some cereal producing soils in Queensland;Black;Aust. J. Soil Res.,1972
3. Total Nitrogen;Bremner,1965
4. Ammonium fixation, release, nitrification, immobilization in high- and low-fixing soils;Drury;Soil Sci. Am. J.,1991
5. Availability of non-exchangeable (fixed) ammonium of manured loessial soil in China;Fan;Acta Pedologica Sinica,1990