Sebastian Matyas Peter Kiefer Christoph Schlieder Sara Kleyer Wisdom about the Crowd: Assuring Geospatial Data Quality Collected in Location-Based Games. 331-336 2011 ICEC http://dx.doi.org/10.1007/978-3-642-24500-8_36 conf/iwec/2011 db/conf/iwec/icec2011.html#MatyasKSK11