Subhasis Bhattacharjee Nabanita Das Distributed Data Gathering Scheduling in Multihop Wireless Sensor Networks for Improved Lifetime. 46-50 2007 conf/iccta/2007 ICCTA http://doi.ieeecomputersociety.org/10.1109/ICCTA.2007.53 db/conf/iccta/iccta2007.html#BhattacharjeeD07