Helena Ahonen Barbara Heikkinen Oskari Heinonen Jani Jaakkola Mika Klemettinen Analysis of Document Structures for Element Type Classification. 24-42 1998 conf/ep/1998poddp PODDP http://link.springer.de/link/service/series/0558/bibs/1481/14810024.htm db/conf/ep/poddp1998.html#AhonenHHJK98