@conference{SBS13,
 author = {Senaratne, Hansi and Broering, Arne and Schreck, Tobias},
 booktitle = {Proceedings of the 16th AGILE International Conference on Geographic Information Science},
 title = {Assessing the credibility of VGI contributors based on metadata and reverse viewshed analysis - An experiment with geotagged Flickr images},
 year = {2013}
}