“…However, a more complicated than ψ(x, y) = e iky ψ(x) dependence of the solutions ψ on y is of interest, and so we will apply some generalizations of our GBDT version (see [8,15,16,22] and references therein) of Bäcklund-Darboux transformation. Such generalizations (for the cases of linear systems of several variables) are given, for instance, in the papers [4,19,20]. In particular, explicit solutions of nonstationary Dirac systems are constructed in [4].…”