Urs Bischoff Martin Strohbach Mike Hazas Gerd Kortuem Constraint-Based Distance Estimation in Ad-Hoc Wireless Sensor Networks. 54-68 2006 conf/ewsn/2006 EWSN http://dx.doi.org/10.1007/11669463_7 db/conf/ewsn/ewsn2006.html#BischoffSHK06