RT Article T1 Public mass murderers and federal mental health background checks JF Law & policy VO 40 IS 2 SP 133 OP 147 A1 Silver, James A2 Horgan, John A2 Fisher, William LA English YR 2018 UL https://krimdok.uni-tuebingen.de/Record/1912670321 DO 10.1111/lapo.12102