major caves, flow routes, the potentiometric surface, and an index to the topographic maps in the Mammoth Cave Region south of the Green River, 2nd edition. Friends of the Karst, Mammoth Cave, KY. Articles Associated Press: Cave Passage Explored Kentucky Living Magazine: Underground Rock Stars Western Scholar Magazine: Underworld Explorer External links Geyser Observation and Study Association Hoffman Environmental Research Institute Bob Gulden's USA Long Cave List Alan Glennon's personal website 1970 births Living people American explorers American geographers American cavers American speleologists Western Kentucky University alumni