Application of laser microprobe (LAMMA 1000) to "fingerprinting" of coal constituents in bituminous coal - Lyons, P.C.; Hercules, D.M.; Morelli, J.J.; Sellers, G.A.; Mattern, D.; Thompson-Rizer, C. L.; Brown, F.; Millay, M.A. (International Journal of Coal Geology, 1987)