db/conf/sigir/HoelscherS99.html Christoph Hölscher Gerhard Strube Searching on the Web: Two Types of Expertise (poster abstract). 305-306 SIGIR1999/P305.pdf 1999 conf/sigir/99 SIGIR http://doi.acm.org/10.1145/312624.312737 db/conf/sigir/sigir99.html#HoelscherS99