Volume 15, no. 1February 2022Survey Articles 5 - 22 Oskolkov Models and Sobolev-Type Equations T.G. Sukacheva 23 - 42 Leontief-Type Systems and Applied Problems A.V. Keller 43 - 59 Semilinear Sobolev Type Mathematical Models A.A. Zamyshlyaeva, E.V. Bychkov 60 - 83 The Non-Classical Models of Mathematical Physics the Multipoint Initial-Final Value Condition S.A. Zagrebina, A.S. Konkina 84 - 100 Semilinear Models of Sobolev Type. Non-Uniqueness of Solution to the Showalter-Sidorov Problem N.A. Manakova, O.V. Gavrilova, K.V. Perevozchikova 101 - 111 Invariant Manifolds of Semilinear Sobolev Type Equations O.G. Kitaeva 112 - 122 Sobolev Type Equations in Spaces of Differential Forms on Riemannian Manifolds without Boundary D.E. ShafranovPersonalia 123 - 127 Georgy Anatolievich Sviridyuk (to Anniversary Since Birth) 128 - 130 Rudakov Konstantin Vladimirovich (21.06.1954 – 10.07.2021). In Memory of Academician Information Science