StegantsevaP. and GrechnevaM. (2024) “Two-dimensional nonisotropic surfaces with flat normal connection and a nondegenerate Grassmann image of constant curvature in the Minkowski space”, Ukrains’kyi Matematychnyi Zhurnal, 76(4), pp. 533 - 551. doi: 10.3842/umzh.v74i4.6743.