1. Bernardos, A., Tarrio, P., Casar, J.R.: A Taxonomy of Mobile Location-Based Services. In: International Conference on e-Business, Barcelona (2007)
2. Bahl, P., Padmanabhan, V.N.: RADAR: An In-Building RF-based User Location and Tracking System. In: INFOCOM 2000. Nineteenth Annual Joint Conference of the IEEE Computer and Communications Societies, Tel Aviv, vol. 2, pp. 775–784 (2000)
3. Harter, A., Hopper, A., Steggles, P., Ward, A., Webster, P.: The Anatomy of a Context-Aware Application. In: 5th Annual ACM/IEEE Int. Conference on Mobile Computing and Networking, Seattle USA, pp. 59–68 (1999)
4. Ni, L.M., Liu, Y., Lau, Y.C., Patil, A.P.: LANDMARC: Indoor Location Sensing Using Active RFID. In: Wireless Networks, pp. 701–710. Springer, Netherlands (2004)
5. Priyantha, N.B., Chakraborty, A., Balakrisnan, H.: The Cricket Location-Support System. In: 6th Int. Conference on Mobile Computing and Networking, Boston, pp. 32–43 (2000)