“…In modern nonlinear sciences some of the most important models are the variable coefficient nonlinear Schrödinger-type ones. Applications include long distance optical communications, optical fibers and plasma physics, see [4], [5], [8], [12], [15], [23], [24], [25], [30], [41], [48], [49], [51], [52], [53], [61], [63], [65] and references therein.…”