[1] G. Ehrlich S. Even T. Tarjan: 
Intersection graphs of curves in the plane. J. Combin. Th. B 21 (1976),  8-20. 
MR 0505857[2] J. Kratochvíl M. Goljan P. Kučera: 
String graphs. Academia, Prague, 1986. 
MR 0865778[3] F. W. Sinden: 
Topology of thin film RC circuits. Bell System Tech. J. (1966), 1639-1662. 
Zbl 0144.45601