1. Beck, A. T.: Depression, 1st edition London: Staples Press 1969.
2. Bradley, J. V.: Distribution-free statistical tests, 1st edition Englewood Cliffs. New Jersey: Prentice-Hall Publishing Co. 1968.
3. Brick, H., Doub, W. H., Perdue, W. C.: Effects of amitriptyline on depressive and anxiety states in penitentiary inmates. Dis. nerv. Syst. 23, 572?578 (1962).
4. Edelstein, E. L.: Amitriptyline in depressive states: A controlled trial. Dis. nerv. Syst. 23, 644?647 (1962).
5. Finney, D. J., Latscha, R., Bennett, B. M., Hsu, P.: Tables for testing significance in 2×2 contigency tables. London-New York: Cambridge University Press 1963.