1. http://www.hxi.com. http://www.hxi.com.
2. http://wilocity.com/about. http://wilocity.com/about.
3. http://www.vubiqnetworks.com. http://www.vubiqnetworks.com.
4. http://gnuradio.org. http://gnuradio.org.
5. http://sine.ni.com/nips/cds/view/p/lang/de/nid/213005. http://sine.ni.com/nips/cds/view/p/lang/de/nid/213005.