@ARTICLE {20156,
author={M.  Ali and S.M. Mumtaz},
doi={10.1109/ACCESS.2016.2598736},
journal={IEEE Access},
title={Energy Efficient Resource Allocation in D2D-Assisted Heterogeneous Networks with Relays},
year={2016},
month={June},
volume={4},
number={2},
pages={4902-4911},
ISSN={2169-3536}
}