@inbook {598,
	title = {Heterogeneous Networks on Multiple Levels},
	booktitle = {Multivariate Network Visualization},
	number = {8380},
	year = {2014},
	pages = {177-208},
	publisher = {Springer},
	organization = {Springer},
	edition = {LNCS State-of-the-Art Survey},
	chapter = {9},
	address = {Heidelberg, New York},
	issn = {978-3-319-06792-6},
	url = {https://www.springer.com/computer/information+systems+and+applications/book/978-3-319-06792-6},
	author = {Falk Schreiber and Kerren, Andreas and Kathy B{\"o}rner and Hans Hagen and Dirk Zeckzer}
}
