Dereppe, J.-M., Boudou, JP., Moreaux, C., & Durand, B. (1983). Structural Evolution of a Sedimentologically Homogeneous Coal Series As a Function of Carbon Content By Solid-state C-13 Nmr. Fuel : the science and technology of fuel and energy, 62(5), 575-579. https://doi.org/10.1016/0016-2361(83)90229-6 (Original work published 1983)