1. Goodchild, M.F.: Citizens as sensors: the world of volunteered geography. GeoJournal 69(4), 211–221 (2007)
2. Coleman, D.J., Georgiadou, Y., Labonte, J., et al.: Volunteered geographic information: the nature and motivation of produsers. International Journal of Spatial Data Infrastructures Research 4(1), 332–358 (2009)
3. Feick, R., Roche, S.: Valuing volunteered geographic information (VGI): Opportunities and challenges arising from a new mode of GI use and production. In: Proceedings of the 2nd GEOValue Workshop, HafenCity University Hamburg, Germany, pp. 75–79 (2010)
4. Zook, M., Graham, M., Shelton, T., Gorman, S.: Volunteered geographic information and crowdsourcing disaster relief: a case study of the Haitian earthquake. World Medical & Health Policy 2(2), 7–33 (2010)
5. Girres, J.F., Touya, G.: Quality assessment of the french OpenStreetMap dataset. Transactions in GIS 14(4), 435–459 (2010)