1. L. Adler, and M. C. Sun . 1968 . Ground control in bedded formations. Bull. 28, Virginia Polytech. Inst., Blacksburg, VA. 226 pp.
2. C. J Booth . 1984 . A numerical model of groundwater flow associated with an underground coal mine in the Appalachian Plateau. PhD dissertation, Dept. of Geo-sciences, Penn State University, University Park, PA. 458 pp.
3. C. J Booth . 1984 . The hydrogeological impact of deep longwall mining Appalachian Plateau, Pennsylvania. Proc. NWWA Conference on the Impact of Mining on Ground Water, Denver, Colo. (Aug. 1984). pp. 360 -379 .
4. R. L. Brown, and R. R. Parizek . 1971 . Shallow ground water flow systems beneath strip and deep coal mines at two sites, Clearfield Co., PA. Coll. Earth & Min. Sci. Spec. Res. Rept. SR-84, Penn State Univ.216 pp.
5. Pore-Water Pressure in the Roof of an Underground Coal Mine in Illinois