“…Bitsadze [7,8], Gushchin [42], Gushchin and Mikhailov [43,44], Eidelman and Zhiratau [14], Il'in and Moiseev [47], Kishkis [50,51], Paneah [67], Roitberg and Sheftel' [73,74], Soldatov [78], and others studied different versions and generalizations of nonlocal problems containing transformations of variables that mapped a boundary to closure of the domain. Special attention was devoted to the solvability nonlocal problems.…”