Probing Supercritical Accretion in Ultraluminous X-ray Source M82 X-1 by means of X-ray Spectral Evolution AnalysisIzatul Hafizah and Kiki VierdayantiEPJ Web Conf., 240 (2020) 07005DOI: https://doi.org/10.1051/epjconf/202024007005