Shad Roundy Dan Steingart Luc Frechette Paul K. Wright Jan M. Rabaey Power Sources for Wireless Sensor Networks. 1-17 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2920&spage=1 2004 conf/ewsn/2004 EWSN db/conf/ewsn/ewsn2004.html#RoundySFWR04