@ARTICLE {21560,
author={C.  Xu and Z.  Zhou and F.  Xiong and S.M. Mumtaz},
doi={10.1109/TII.2017.2777139},
journal={IEEE Transactions on Industrial Informatics},
title={Energy-efficient Vehicular Heterogeneous Networks for Green Cities},
year={2017},
month={November},
volume={87},
number={36},
pages={65-75},
ISSN={1551-3203}
}