Hanjiang Luo Yiyang Zhao Zhongwen Guo Siyuan Liu Pengpeng Chen Lionel M. Ni UDB: Using Directional Beacons for Localization in Underwater Sensor Networks. 551-558 2008 ICPADS http://dx.doi.org/10.1109/ICPADS.2008.31 conf/icpads/2008 db/conf/icpads/icpads2008.html#LuoZGLCN08