17 invited lectures at mathematical seminars and international conferences Budva, Cheju, Chinju, Chisinau, Gomel, Islamabad, Kharkov, Luhansk, Novi Sad, Plovdiv, Seoul, Saratov, Skopje, Volgograd.   34 talks at international conferences Belorussia, Bulgaria, Czech Republic, Estonia, Georgia, Germany, Macedonia, Moldova, Poland, Romania, Russia (Moscow, Novosibirsk, Saratov, Volgograd), Slovakia, South Korea, Ukraine, Yugoslavia.   Member of the Program or Scientific Committee 20th Pure Mathematical Conference 2019, Islamabad (Pakistan), 2016. 19th Pure Mathematical Conference 2018, Islamabad (Pakistan), 2015. 18th Pure Mathematical Conference 2017, Islamabad (Pakistan), 2014. 4th Conference of Mathematical Society of the Republic of Moldova, Chisinau (Moldova), 2017. 17th Pure Mathematical Conference 2016, Islamabad (Pakistan), 2016. 16th Pure Mathematical Conference 2015, Islamabad (Pakistan), 2015. 15th Pure Mathematical Conference 2014, Islamabad (Pakistan), 2014. The Third Conference of Mathematical Society of the Republic of Moldova, Chisinau, 2014. 14th Pure Mathematical Conference 2013, Islamabad (Pakistan), 2013. 10th International Conference "Algebra and Number Theory: Problems and Applications", Volgograd, 2012. IEEE World Congress on Computational Intelligence, Brisbane (Australia), 2012. 13th Pure Mathematical Conference 2012, Islamabad (Pakistan), 2012. 8th International Algebraic Conference in Ukraine, Luhansk, 2011. International Conference on Mathematics of Date, Allahabad (India), 2010. 5th Baltic-Nord Workshop: Algebra, Geometry, and Mathematical Physics, Bedlewo (Poland), 2009. 10th Pure Mathematical Conference 2009, Islamabad (Pakistan), 2009. 9th Pure Mathematical Conference 2008, Islamabad (Pakistan), 2009. 8th Pure Mathematical Conference 2007, Islamabad (Pakistan), 2007. 7th Pure Mathematical Conference 2006, Islamabad (Pakistan), 2006. Second International Seminar "Universal Algebra, Number Theory and Applications", Volgograd, 2005. 5th International Algebraic Conference in Ukraine, Odessa, 2005. 6th Pure Mathematical Conference 2005, Islamabad (Pakistan), 2005. 5th Pure Mathematical Conference 2004, Islamabad (Pakistan), 2004. First Conference of the Mathematical Society of Moldova, Kishinev, 2001 (sponsored by UNESCO). Member of the Organizing Committee International Conference in Algebras and Related Topics, Hong Hong, 2002 (satellite conference of ICM 2002) (info) Algebra and Logic, Novi Sad (Yugoslavia), 1998. Moderator 7th International Algebraic Conference in Ukraine, Kharkov, 2009. 6th International Algebraic Conference in Ukraine, Kamyanets-Podilsky, 2007. INTAS Workshop, Tbilisi, Georgia 2006. INTAS Workshop, Chisinau, Moldova 2005.