00770nam 2200169z- 450 9910712526103321(CKB)5470000002494894(EXLCZ)99547000000249489420230509c2018uuuu -u- -engEnhancing school safety using a threat assessment model : an operational guide for preventing targeted school violenceU.S. Department of Homeland Security, United States Secret Service, National Threat Assessment CenterWashington, D.CEnhancing school safety using a threat assessment model BOOK9910712526103321Enhancing school safety using a threat assessment model : an operational guide for preventing targeted school violence3259141UNINA