Siu-Wing Cheng Jiongxin Jin Antoine Vigneron Yajun Wang Approximate Shortest Homotopic Paths in Weighted Regions. 109-120 2010 ISAAC (2) http://dx.doi.org/10.1007/978-3-642-17514-5_10 conf/isaac/2010-2 db/conf/isaac/isaac2010-2.html#ChengJVW10