Dereppe, J.-M., & Moreaux, C. (1987). A Limitation of C-13 Cp Mas Nmr-spectroscopy for the Study of Treated Coals. Fuel : the science and technology of fuel and energy, 66(7), 1008-1009. https://doi.org/10.1016/0016-2361(87)90344-9 (Original work published 1987)