Situations Endowed with Lattice Structure. - Nikolai G. Nikolov (FQAS, 2000)

Remark on the Pseudo-Fixed Points of the Intuitionistic Fuzzy Logic Operators. - Krassimir T. Atanassov; Nikolai G. Nikolov (Int. J. Uncertain. Fuzziness Knowl. Based Syst., 2001)

Remark on Two Operations over Intuitionistic Fuzzy Sets. - Krassimir T. Atanassov; Nikolai G. Nikolov; Hristo T. Aladjov (Int. J. Uncertain. Fuzziness Knowl. Based Syst., 2001)

A Logic of Inequalities. - Nikolai G. Nikolov (AIMSA, 2004)

A Converse of the Gauss-Lucas Theorem. - Nikolai G. Nikolov; Blagovest Sendov (Am. Math. Mon., 2014)