1. Beard, J. (1973).Turfgrass Science and Culture.Prentice Hall, Englewood Cliffs, NJ, USA. 658 pp.
2. Emmons, R. D. (2000).Turfgrass Science and Management.3rd. Edition. Delmer Thompson Learning, Albany, New York, NY, USA. 544 pp.
3. Hopkins, W. G. (1995).Introduction to Plant Physiology.John Wiley and Son, Inc., New York, USA. 464 pp.
4. Page, A. L., Miller, R. H. and Keeney, D. R. (1992).Methods of Soil Analysis. Part 2. Chemical and Microbiological Properties Methods.Agronomy No 9. American Society of Agronomy, Madison, WI, USA. 1159 pp.