Jonathan Lester Carl Hartung Laura Pina Ryan Libby Gaetano Borriello Glen Duncan Validated caloric expenditure estimation using a single body-worn sensor. 225-234 2009 UbiComp http://doi.acm.org/10.1145/1620545.1620579 conf/huc/2009 db/conf/huc/ubicomp2009.html#LesterHPLBD09