Bell, J.C., W.L. Daniels, and C.E. Zipper. 1989. The practice of "approximate original Contour" in the Central Appalachians. I. Slope stability and erosion potential. Landscape and Urban Planning. 18:127-138.

Daniels, W. L., J. C. Bell, and C. E. Zipper. 1987. The long term stability, land use potential, and erosivity of surface mined lands returned to their approximate original contour in the central Appalachians. In: Proceedings, National Meeting of the American Society for Surface Mining and Reclamation. Billings, Montana.

Bell, J. C. and W. L. Daniels. 1985. Four case studies of slope stability on surface mined lands returned to approximate original contour in SW Virginia p. 243-247. In: Proc. 1985 Symposium on Surface Mining Hydrology, Sedimentology and Reclamation. Univ. of Ky., Lexington, KY.