1. Oxera Consulting. 2013. What is the economic impact of Geo services? http://www.oxera.com/LatestThinking/Publications/Reports/2013/What-is-the-economic-impact-of-Geo-services.aspx
2. Henttu, H., Izaret, J.M. and Potere, D. 2012. Geospatial services: A $1.6 trillion growth engine for the US economy. San Francisco, CA, USA: The Boston Consulting Group.
3. Technavio. 2016. Global Mobile GIS Market 2016-2020. https://www.technavio.com/report/global-enterprise-application-mobile-gis-market?utm_source=T4& utm_medium=BW&utm_campaign=Media
4. Gang, S.M., Choi, H.W., Kim, D.R. and Choung, Y.J., 2016. A Study on the Construction of the Unity 3D Engine Based on the WebGIS System for the Hydrological and Water Hazard Information Display. Procedia Engineering, 154, 138--145.
5. Liang, J., Shen, S., Gong, J., Liu, J. and Zhang, J., 2017. Embedding user-generated content into oblique airborne photogrammetry-based 3D city model. International Journal of Geographical Information Science, 31(1), 1--16.