Frei, W.; Hertzmann, P.; Lehner, P.; Müller, Stefanie; Olivier, R.; Pfiffner, Othmar-Adrian; Steck, A.; Valasek, P. (1989). Geotraverses across the Swiss Alps. Nature, 340(6234), pp. 544-548. Macmillan Journals Ltd. 10.1038/340544a0