Jane Greenberg Kristen A. Bullard M. L. James Evelyn Daniel Peter White Student Comprehension of Classification Applications in a Science Education Digital Library. 560-567 2002 conf/ercimdl/2002 ECDL http://link.springer.de/link/service/series/0558/bibs/2458/24580560.htm db/conf/ercimdl/ecdl2002.html#GreenbergBJDW02