“…However, to be specific, through this paper we focus on three basic models which have recently attracted a great deal of attention to describe the behavior close to a QCP of many materials subject to extensive experimental studies in the latest years. They are characterized by [1,2,3,4,5,6,11,12,13,14,15,16,17,18,19,20,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38]:…”