Ioannis Chatzigiannakis Athanasios Kinalis Sotiris E. Nikoletseas Sink mobility protocols for data collection in wireless sensor networks. 52-59 2006 MOBIWAC http://doi.acm.org/10.1145/1164783.1164793 conf/mobiwac/2006 db/conf/mobiwac/mobiwac2006.html#ChatzigiannakisKN06