A Certain Conception of the Calculus of Rough Sets. - Zbigniew Bonikowski (Notre Dame J. Formal Log., 1992)

Algebraic Structures of Rough Sets. - Zbigniew Bonikowski (RSKD, 1993)

Extensions and Intentions in the Ruogh Set Theory. - Zbigniew Bonikowski; Edward Bryniarski; Urszula Wybraniec-Skardowska (Inf. Sci., 1998)

Algebraic Structures of Rough Sets in Representative Approximation Spaces. - Zbigniew Bonikowski (RSKD, 2003)

Rough Sets and Vague Sets. - Zbigniew Bonikowski; Urszula Wybraniec-Skardowska (RSEISP, 2007)

Vagueness and Roughness. - Zbigniew Bonikowski; Urszula Wybraniec-Skardowska (Trans. Rough Sets, 2008)

Unit Operations in Approximation Spaces. - Zbigniew Bonikowski (RSCTC, 2010)

Rough Pragmatic Description Logic. - Zbigniew Bonikowski; Edward Bryniarski; Urszula Wybraniec-Skardowska (Rough Sets and Intelligent Systems (2), 2013)

Theory of tailor automata. - Jacek Waldmajer; Zbigniew Bonikowski; Sebastian Sakowski (Theor. Comput. Sci., 2019)