1. Dewey, W. L., Snyder, J. W., Harris, L. S., Howes, J. F.: The effect of narcotics and narcotic antagonists on the tail-flick response in spinal mice. J. Pharm. Pharmacol. 21, 548?550 (1969).
2. Dixon, W. J., Massey, F. J.: Introduction to statistical analysis. New York: McGraw Hill 1957.
3. Fraser, H. F., Harris, L. S.: Narcotic and narcotic antagonist analgesics. Ann. Rev. Pharmacol. 7, 277?300 (1967).
4. Grotto, M., Sulman, F. G.: Modified receptacle method for animal analgesimetry. Arch. int. Pharmacodyn. 165, 152?159 (1967).
5. Grumbach, L.: The prediction of analgesic activity in man by animal testing. In: R. S. Knighton and P. R. Dumke, eds.): Pain., Henry Ford Hospital International Symposium, pp. 163?182. Boston: Little, Brown, 1966.