Ahn, S. S., H. . S. Kim, S.-Z. Song, and Y. B. Jun. “Dokdo Filters and Deductive Systems of Sheffer Stroke Hilbert Algebras”. European Journal of Pure and Applied Mathematics, vol. 16, no. 3, July 2023, pp. 1862-77, doi:10.29020/nybg.ejpam.v16i3.4872.