Billinsley, K. (1991, Spring). School safety index. School Safety, 26.
Callahan, C.M., & Rivara, S.P. (1992). Urban high school youth and handguns: A school-based survey. Journal of the American Medical Association, 267, 3038-3042.
Glazer, S. (1992, September 11). Violence in schools. CQ Researcher, 787-803.