@InBook{virt,
	author = 	{E. Köppen and G. Neumann},
	title = 	{Classification in the Information Age},
	year = 	{1999},
	month = 	{February},
	category = 	{NM, education},
	ps = 	{http://nm.wu-wien.ac.at/research/publications/Gfkl98-EK.ps},
	pdf = 	{http://nm.wu-wien.ac.at/research/publications/Gfkl98-EK.pdf},
	editor = 	{W. Gaul, H. Locarek-Junge},
	chapter = 	{Virtualization of Course Structures through Adaptive Internet Techniques},
	publisher = 	{Springer Verlag},
}