(1) USA (Tempa, Florida): International Conference (August 19-26, 1992): Presented a paper in the First World Congress of Nonlinear Analysts.
    (2) Hungary: Visiting Scientist
     (October 15-December 28, 1993) University of Szeged, Szeged and Eotvos Lorand University , Budapest under Exchange Programme of Indian National Science Academy and Hungarian Academy of Sciences.
    (3) Turkey:

    (i) Visiting Professor (September 1- October 29, 2001): Sakarya University (Sakarya) and Y. Y. University (Van) under the UN Programme UNISTAR-TOKTEN of TUBITAK.
    (ii) Visiting Professor (May 25-June 25, 2007): Firat University (Elazig) and Inonu University (Malatya) under FUBAP.
    (iii) Visiting Professor (June 20-July 18, 2010): Yildiz Tech. Univ., Istanbul Ticaret Univ., Fatih Univ., and Malteppe Univ., Istanbul under TUBITAK.
    (iv) International Conference (June 28-July 03, 2011): Plenary talk in the "International Conference on Applied Analysis And Algebra" at the Yildiz Technical University, Istanbul.
    (v) International Conference (June 02-June 05, 2013): Plenary talk in the "International Conference on Applied Analysis And Mathematical Modeling " at the Yildiz Technical University, Istanbul.
    (vi) Visiting Professor (August 19-September 14, 2013): Fatih University, Istanbul under TUBITAK.
    (vii) International Conference (September 12-14, 2013): Plenary talk "Infinite system of differential equations in some BK spaces" in The Algerian-Turkish International days on Mathematics 2013, Fatih University, İstanbul, Turkey.

    (viii) International Conference (June 08-June 12, 2015): Keynote Speaker in the "International Conference on Applied Analysis And Mathematical Modeling " at the Yildiz Technical University, Istanbul.

    (4) Thailand:

    (i) Visiting Professor (August 1-August 31, 2002): Chiang Mai University.
    (ii) International Conference (December, 7-9, 2010): Contributed talk in the "International Conference on Mathematical Analysis (ICMA 2010)" at Bangkok.
    (5) Serbia: International Conference
    (September 24-28, 2003): Invited talk and chaired a session in the "International Workshop on Modern Functional Analysis, Operator Operator Theory,Summability and Applications (MFA-03)" at the University of Nis.
    (6) Switzerland: International Conference (July 16-20, 2007): Contributed talk in the "International Congress of Industrial and Applied Mathematics (ICIAM 07)".
    (7) UK: International Conference (July 13-18, 2009): Invited talk in the 7th International ISAAC Congress at Imperial College of London.
    (8) Saudi Arabia:

    (i) Visiting Professor (May 16- June 13, 2011): Tabuk University, Tabuk.
    (ii) Visiting Professor (May 18- June 04, 2012): Tabuk University, Tabuk.
    (iii) Visiting Professor (May 18- June 03, 2015): Tabuk University, Tabuk, and King Abdulaziz University, Jeddah.

    (9) Malaysia:

    (i) Visiting Scientist (August 27- September 25, 2012): University Putra Malaysia.

    (ii) International Conference (May 27-30, 2014): Invited talk in the International Conference and Workshop on Mathematical Analysis 2014 1 at University Putra Malaysia.
    (11) Albania: International Conference (May 30- June 01, 2013): Invited talk in the "Western Balkan Conference of Mathematical Sciences" at the University of Elbasan, Albania.              

    (12) Taiwan: International Conference (December 20--22, 2013): Invited talk in the "International Conference on Nonlinear Analysis And Optimization" at National Sun Yat-sen University, Kaohsiung,Taiwan.                                      

    (13) Kazakhstan: International Conference (September 11--13, 2014): Invited talk in the "Second International Conference on Analysis And Applied Mathematics" at M. Auezov South Kazakhstan State University, Shymkent, Kazakhstan.