Early warning analysis of electricity sales based on multi-factor correlation analysisCHEN Hai, CUI Yan - yan, MA li, LIU Wei, WANG Jun, YUAN Shuai, Guo Ju, HUANG Yi and Dong Xiao–jingE3S Web Conf., 53 (2018) 02007DOI: https://doi.org/10.1051/e3sconf/20185302007