Jonas Holmerin Improved Inapproximability Results for Vertex Cover on k -Uniform Hypergraphs. 1005-1016 2002 conf/icalp/2002 ICALP http://link.springer.de/link/service/series/0558/bibs/2380/23801005.htm db/conf/icalp/icalp2002.html#Holmerin02