Hoelloch Cave Research Association - Dedicated to the exploration and survey of the karst area of the Muotha Valley. Includes history of the Hoelloch system, photo gallery, literature and contact information. - http://www.hoelloch.org
Association of Cavers of the Hogant Region (HRH) - Founded in 1979. Coordinates exploration and scientific research, exchanges data and information, and promotes conservation. Includes contacts. [German, French and English]. - http://www.sghbern.ch/page/hrh/hrh.html#E