There is a book:
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Faszination Blautopf Vorstoss in unbekantne H?hlenwelten [Fascination Blautopf Venture into unknown Cave-worlds ]by Arbeitsgemindschaft Blautopf (HG) 2009 136 pp, 75 colour plates, mainly whole page. Jan Thorbecke Verlag, D-73760 Ostfildern. ISBN 978-3-7995-0831-5
The Blautopf or Blue Pot is a Vaclusian spring in the town of Blaubeuren in the Swabian Alb in Southern Germany, it is the second largest karst spring in Germany. It is a cavers? dream come true. Since 1957 cave divers have been pushing the sump and finally they broke into an air space. This turned out be a cave system nearly 7 km long. Soon a new entrance was made and the explorers had a dry way in.
The book is clearly written from the perspective of cave diving research and has set itself the goal to give the reader the fascination of this cave system and the extreme difficulties of exploration. The book describes in detail the numerous cave dives, and underground bivouacs. Illustrated with stunning photographs, mainly from the talented hands of Andreas K?cha is a vivid document of the caving under extreme conditions. The book was published by the Association Blautopf and co-written by 11 authors who participate actively in the ongoing exploration of the cave. The excellent print quality and binding are coupled with a pleasing price. Also included is a general plan and a plan of the previously explored cave system, which facilitates orientation when reading the book. There are also descriptions of the archaeological finds from the spring including late-medieval pottery and Celtic swords. A foreword by Hubert Trimmel rounds off the book.
PM me if you want a copy.