Poppe, Edwin (2001). "Effects of changes in GNP and perceived group characteristics on national and ethnic stereotypes in central and eastern Europe". Journal of Applied Social Psychology. 31 (8): 1689–1708. doi:10.1111/j.1559-1816.2001.tb02746.x.
Hovland, C. I.; Sears, R. R. (1940). "Minor studies of aggression: VI. Correlation of lynchings with economic indices". Journal of Psychology: Interdisciplinary and Applied. 9 (2): 301–310. doi:10.1080/00223980.1940.9917696.