1. Agnew, N. M.: The relative value of self report and objective tests in assessing the effects of amphetamine. J. Psychiat. Res. 2, 85?100 (1964).
2. Beecher, H. K.: Some remarks on quantitative studies of subjective responses to drugs. In: Psychopharmacology. A Review of Progress 1957?1967, pp. 973 to 977. D. H. Efron (ed.). Washington: U.S. Government Printing Office 1968.
3. Broadbent, D. E.: Perception and communication. London: Pergamon Press 1958.
4. Bruner, J. S.: Going beyond the information given, in contemporary approaches to cognition. Cambridge: Harvard Univ. Press 1957.
5. Cole, J. O.: Peeking through the double blind. In: Psychopharmacology. A review of progress 1957?1967, pp. 979?984. D. H. Efron (ed.). Washington: U.S. Government Printing Office 1968.