@ARTICLE{9372931, author={Shi, Shanghao and Xiao, Yang and Lou, Wenjing and Wang, Chonggang and Li, Xu and Hou, Y. Thomas and Reed, Jeffrey H.}, journal={IEEE Internet of Things Journal}, title={Challenges and New Directions in Securing Spectrum Access Systems}, year={2021}, volume={8}, number={8}, pages={6498-6518}, doi={10.1109/JIOT.2021.3064583}}