Ralf Klinkenberg Learning drifting concepts: Example selection vs. example weighting. 281-300 2004 8 Intell. Data Anal. 3 http://iospress.metapress.com/openurl.asp?genre=article&issn=1088-467X&volume=8&issue=3&spage=281 db/journals/ida/ida8.html#Klinkenberg04