P. Krus, and J. Nyman. Proceedings of the 22nd international Congress of Aeronautical Sciences, International Council of the Aeronautical Sciences : American Institute of Aeronautics and Astronautics : Optimage Ltd., (September 2000)
J. Zhao, H. Zheng, and G. Yang. New Frontiers in Dynamic Spectrum Access Networks, 2005. DySPAN 2005.
2005 First IEEE International Symposium on, page 259-268. (2005)