Variable-Range Approximate Systems Induced by Many-Valued L-Relations. - Aleksandrs Elkins; Sang-Eon Han; Alexander P. Sostak (IPMU (3), 2014)

On a Category of Extensional Fuzzy Rough Approximation L-valued Spaces. - Aleksandrs Elkins; Alexander P. Sostak; Ingrida Uljane (IPMU (2), 2016)

Many-level fuzzy rough approximation spaces induced by many-level fuzzy preorders and the related ditopological structures. - Alexander P. Sostak; Ingrida Uljane; Aleksandrs Elkins (EUSFLAT Conf., 2019)