1. Lange, C.G.: cited by Zangwill, O.L. in Depression, edited by Davies, E.B., Cambridge University Press, 1964.
2. Mourning and Melancholia;Freud,1917
3. The Phenomena of Depressions;Crinker,1961
4. An Inventory for Measuring Depression;Beck;Arch. Gen. Psych.,1961
5. A Rating Scale for Depression;Hamilton;J. of Neurology Neurosurgery, and Psychiatry,1960