1. A. F, Causes of crime, pp. 76 -98, Univ. of Pennsylvania Press, Philadelphia (1938);
2. W. A. Bonger, Criminality and economic conditions, 619 pp., Little & Brown, Boston (1916).
3. 2. G. Aschaffenburg, Crime and its repression , pp. 75 -76 , Little & Brown, Boston (1913 ).
4. 3. S. Hurwitz, Criminology , p. 279 , Allen & Unwin, London (1952 ).