Butterfield, F. (1999). F.B.I. study finds gun use in violent crimes declining.
Cita Chicago Style (17a ed.)Butterfield, Fox. F.B.I. Study Finds Gun Use in Violent Crimes Declining. 1999.
Cita MLA (9a ed.)Butterfield, Fox. F.B.I. Study Finds Gun Use in Violent Crimes Declining. 1999.
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