Paolo Fogliaroni Jan Oliver Wallgrün Eliseo Clementini Francesco Tarquini Diedrich Wolter A Qualitative Approach to Localization and Navigation Based on Visibility Information. 312-329 2009 COSIT http://dx.doi.org/10.1007/978-3-642-03832-7_19 conf/cosit/2009 db/conf/cosit/cosit2009.html#FogliaroniWCTW09