“…Examples are reported in refs [8,30,39,40,43,44,46,54,55,57,[78][79][80][81][82][83][84][85][86] and some of them are briefly discussed below. Examples are reported in refs [8,30,39,40,43,44,46,54,55,57,[78][79][80][81][82][83][84][85][86] and some of them are briefly discussed below.…”