1. Cognitive radio: making software radios more personal;J Mitola;IEEE Personal Communications,1999
2. Cognitive radio: brain-empowered wireless communications;S Haykin;IEEE J. Selected Areas Communication,2005
3. Approaches to spectrum sharing;J M Peha;IEEE Communications Magazine, Regulatory and Policy Issues,2005
4. Spectrum Challenges and Solutions by Cognitive Radio: An Overview;K Sridhara;Wireless Personal Communications,2008