Yelena Nakhimovsky Dean Eckles Jens Riegelsberger Overcoming challenges in mobile UX research methods and tools. 2747-2750 2009 CHI Extended Abstracts http://doi.acm.org/10.1145/1520340.1520397 conf/chi/2009a db/conf/chi/chi2009a.html#NakhimovskyER09