CHIARLE M. & POWERS P.S., 1994, Surficial horizontal displacements on Slumgullion landslide, Hinsdale County, Colorado – 1985 to 1990 (Determined by direct visual comparison), 1994,
URL: http://www.cnr.it/prodotto/i/258501

Data from https://intranet.cnr.it/people/