RT Article T1 Policy recommendations for countering mass shootings in the United States JF Criminology & public policy VO 19 IS 1 SP 9 OP 15 A1 Nagin, Daniel 1948- A2 Koper, Christopher S. A2 Lum, Cynthia LA English YR 2020 UL https://krimdok.uni-tuebingen.de/Record/1691186724 K1 Mass shootings K1 USA K1 Recommendations DO 10.1111/1745-9133.12484