Wouter Weerkamp Krisztian Balog Maarten de Rijke Using Contextual Information to Improve Search in Email Archives. 400-411 2009 ECIR http://dx.doi.org/10.1007/978-3-642-00958-7_36 conf/ecir/2009 db/conf/ecir/ecir2009.html#WeerkampBR09