@article{ref1,
title="Spring Guns",
journal="American journal of police science",
year="1930",
author="Tangen, E",
volume="1",
number="3",
pages="307-312",
abstract="<p>[Abstract unavailable]</p>",
language="",
issn="1547-6154",
doi="",
url="http://dx.doi.org/"
}