Pinar Heggernes Daniel Meister Yngve Villanger Induced Subgraph Isomorphism on Interval and Proper Interval Graphs. 399-409 2010 ISAAC (2) http://dx.doi.org/10.1007/978-3-642-17514-5_34 conf/isaac/2010-2 db/conf/isaac/isaac2010-2.html#HeggernesMV10