Change of parameters in molecular structure of Donbas coals under the influence of external factorsLiudmyla Pymonenko, Oleksandr Burchak, Oleksandr Balalaiev, Valentyna Slobodiannykova and Yurii SierikovE3S Web Conf., 109 (2019) 00077DOI: https://doi.org/10.1051/e3sconf/201910900077