University "La Sapienza" , Switzerland
Interzonal General de Agudos. Haedo. Buenos Aires. Argentina.
Department “Policlinico Luigi di Liegro” Rome Italy
University Leipzig, Habilitation, Germany
Department of Orthopedics at Ibn Sina Medical College, Bangladesh
Sheikh Hasina National Institute of Burn and Plastic Surgery, Bangladesh
University of Bisha, Saudi Arabia
West China Hospital of Sichuan University, China
