<?xml version="1.0"?>
<dblp>
<article key="journals/entcs/MiddelkoopHKL08" mdate="2008-01-30">
<author>Ronald Middelkoop</author>
<author>Cornelis Huizing</author>
<author>Ruurd Kuiper</author>
<author>Erik J. Luit</author>
<title>Invariants for Non-Hierarchical Object Structures.</title>
<pages>211-229</pages>
<year>2008</year>
<volume>195</volume>
<journal>Electr. Notes Theor. Comput. Sci.</journal>
<ee>http://dx.doi.org/10.1016/j.entcs.2007.08.034</ee>
<url>db/journals/entcs/entcs195.html#MiddelkoopHKL08</url>
</article>
</dblp>
