1. Coombs, C. H., Dawes, R. M., &Tversky, A. (1970).Mathematical psychology: An elementary introduction. Englewood Cliffs, NJ: Prentice-Hall.
2. Guilford, J. P, &Fruchter, B. (1978).Fundamental statistics in psychology and education (6th ed.). New York: McGraw-Hill.
3. Hemenway, K., &Armitage, H. (1984). Proposed syntax standard for UNIX system commands.Proceedings of the 1984 Summer Usenix Conference, Washington, DC El Cerito, CA: Userux Association.
4. Keppel, G. (1973).Design and analysis: A researcher’s handbook. Englewood Cliffs, NJ: Prentice-Hall.
5. Kerlinger, F. N., &Pedhazur, E. J. (1973).Multiple regression in behavioral research. New York Holt Rinehart Winston.