Bipolar fuzzy subalgebras and bipolar fuzzy ideals of BCK/BCI-algebras. Lee, Kyoung Ja — 2009 Bulletin of the Malaysian Mathematical Sciences Society. Second Series
Graphs based on BCK/BCI-algebras. Jun, Young Bae; Lee, Kyoung Ja — 2011 International Journal of Mathematics and Mathematical Sciences
Fuzzy ideals in BE-algebras. Song, Seok Zun; Jun, Young Bae; Lee, Kyoung Ja — 2010 Bulletin of the Malaysian Mathematical Sciences Society. Second Series