Liping Wang Yusheng Ji Fuqiang Liu A Novel Centralized Resource Scheduling Scheme in OFDMA-Based Two-Hop Relay-Enhanced Cellular Systems. 113-118 2008 WiMob http://dx.doi.org/10.1109/WiMob.2008.50 conf/wimob/2008 db/conf/wimob/wimob2008.html#WangJL08