Timothy Sohn Alex Varshavsky Anthony LaMarca Mike Y. Chen Tanzeem Choudhury Ian E. Smith Sunny Consolvo Jeffrey Hightower William G. Griswold Eyal de Lara Mobility Detection Using Everyday GSM Traces. 212-224 2006 conf/huc/2006 Ubicomp http://dx.doi.org/10.1007/11853565_13 db/conf/huc/ubicomp2006.html#SohnVLCCSCHGL06