@ARTICLE{4595662, author={Ren, Kui and Lou, Wenjing and Zhu, Bo and Jajodia, Sushil}, journal={IEEE Transactions on Vehicular Technology}, title={Secure and Efficient Multicast in Wireless Sensor Networks Allowing Ad hoc Group Formation}, year={2009}, volume={58}, number={4}, pages={2018-2029}, doi={10.1109/TVT.2008.2003961}}