@article{ref1,
title="Boundary specification and structural models of elite systems: Social circles revisited",
journal="Social networks",
year="1984",
author="Urban Pappi, Franz",
volume="6",
number="1",
pages="79-95",
abstract="<p>[Abstract unavailable]</p>",
language="",
issn="0378-8733",
doi="10.1016/0378-8733(84)90005-4",
url="http://dx.doi.org/10.1016/0378-8733(84)90005-4"
}