TY  - RPRT
TI  - Slope angle distribution of coal beds with strippable reserves
AU  - Kenneth John Englund
AU  - M. J. Bergin
AU  - M.D. Carter
AU  - C.R. Meissner
AU  - J.B. Roen
PY  - 1977
DO  - 10.3133/ofr77213
UR  - https://pubs.usgs.gov/publication/ofr77213
ID  - ofr77213
ER  -