USA (2 times), UK (3 times), Canada (2 times), China, India (10 times), Hong Kong, Singapore (2 times), Thailand (3 times), Saudi Arabia (2 times) Vietnam, Cambodia and Malaysia.
Ottawa University, Alberta University, Canada Aberdeen University, UK University of Fisheries Nha Trang, Vietnam; California University, Berkley, USA. Calcutta University, Madras University, Jadavpur University, Acharya Nagarjuna University, A.P. India Assam University, Silchar, India; North Bengal University, India; Vikrama Simhapuri University, Nellore, A.P. India; Kasetsart University, Bangkok, Thailand.