References
- Lewis AJ. Melancholia: a clinical survey of depressive states. Journal of Mental Science 1934; 80: 277–378
- Lewis AJ. Melancholia: prognostic study and case material. Journal of Mental Science 1936; 82: 488–558
- Miller S. Experimental Design and Statistics. London, Routledge 1984
- Siegel S. Nonparanietric Statistics for the behavioural sciences. McGraw-Hill, New York 1956