@book{ 0-1428529926, title = {Program of the 2011 National Convention: Glenwood Springs, Colorado July 18-22, 2011}, series = {1 Beil.: 3D-Brille}, author = {Kolstad, Rob}, editor = {Kolstad, Rob}, address = {Huntsville, Ala.}, publisher = {National Speleogical Society}, year = {2011}, language = {English}, url = {https://swbplus.bsz-bw.de/bsz358529921inh.htm}, url = {https://katalog.ub.tu-freiberg.de/Record/0-1428529926} }