@book {Fra98,
	title = {Minimalistic visual navigation},
	series = {Fortschr.-Ber. VDI Reihe 8},
	number = {739},
	year = {1998},
	publisher = {VDI Verlag},
	organization = {VDI Verlag},
	address = {D{\"u}sseldorf},
	isbn = {3-18-373908-9}
}
