PUBLICATIONS OF THE RESEARCH INSTITUTE FOR MATHEMATICAL SCIENCES , vol. 21, no. 4, page. 807 - 818, 1985-01
Colloquium, Department of Mathematical Science, Lahore University of Management Sciences(LUMS), Pakistan, 2008-03-14
3rd International Conference on 21st Century Mathematics 2007, 2007-03-07
International Conference on Applied Combinatorics and Graph Theory, 2006-12-21
International Conference on Mathematics Ulaanbaatar, Monglia, 2006-07-25
대한수학회 인천-경기-강원지부, 2008년도 춘계연구발표회, 강릉대학교, 2008-06-13