M. Schrapel, A. Finger, J. Meyer, M. Rohs, J. Schöning, and A. Voit. Proceedings of the 2018 ACM International Joint Conference and 2018 International Symposium on Pervasive and Ubiquitous Computing and Wearable Computers, page 660--661. New York, NY, USA, ACM, (2018)
A. Asahara, K. Maruyama, A. Sato, and K. Seto. International Conference on Advances in Geographic Information Systems (SIGSPATIAL), page 25--33. New York, NY, USA, ACM, (2011)