<?xml version="1.0"?>
<dblp>
<article key="journals/jcss/AshleyBBCDK09" mdate="2009-05-05">
<author>Mary V. Ashley</author>
<author>Tanya Y. Berger-Wolf</author>
<author>Piotr Berman</author>
<author>Wanpracha Art Chaovalitwongse</author>
<author>Bhaskar DasGupta</author>
<author>Ming-Yang Kao</author>
<title>On approximating four covering and packing problems.</title>
<pages>287-302</pages>
<year>2009</year>
<volume>75</volume>
<journal>J. Comput. Syst. Sci.</journal>
<number>5</number>
<ee>http://dx.doi.org/10.1016/j.jcss.2009.01.002</ee>
<url>db/journals/jcss/jcss75.html#AshleyBBCDK09</url>
</article>
</dblp>
