Information on the web
Sinkholes in PA
Florida sinkholes are not totally similar to sinkholes in Pennsylvania but the mechanisms of formation are generally the same.
The Karst Pages
- Info on dye tracing and general karst aquifer info from Western Kentucky Univ.
Foose, Richard M. (1953) "Ground-water Behavior in the Hershey Valley, Pennsylvania", Geological Society of America Bulletin, v. 64, p. 623-645.
Newton, J.G. (1987) Development of Sinkholes Resulting From Man's Activities in the Eastern United States. US Geological Survey, Circular 968.
White, William B. (1988) Geomorphology and Hydrology of Karst Terrains. Oxford University Press.