@article{ref1,
title="Air conflict frequency calculations",
journal="Transportation research part B: methodological",
year="1985",
author="Friedman, Moshe F.",
volume="19",
number="1",
pages="15-16",
abstract="A calculation due to Schmidt is discussed.<p /><p>Language: en</p>",
language="en",
issn="0191-2615",
doi="10.1016/0191-2615(85)90026-8",
url="http://dx.doi.org/10.1016/0191-2615(85)90026-8"
}