1. RTL-SDR. http://sdr.osmocom.org/trac/wiki/rtl-sdr. RTL-SDR. http://sdr.osmocom.org/trac/wiki/rtl-sdr.
2. Passive detection of situations from ambient FM-radio signals
3. Sigg S. Scholz M. Shi S. Ji Y. and Beigl M. RF-sensing of activities from non-cooperative subjects in device-free recognition systems using ambient and local signals. IEEE Trans. Mobile Computing PrePrints (2013) 1--14. Sigg S. Scholz M. Shi S. Ji Y. and Beigl M. RF-sensing of activities from non-cooperative subjects in device-free recognition systems using ambient and local signals. IEEE Trans. Mobile Computing PrePrints (2013) 1--14.