2001-2002, Xincheng Yao, Beijing, China, Institute of Physics and Applied Optics.

2003-2005, Irina Topchiy, Russia, Rostor State University (Rostor-on-Don, Russia)

2004-2005, Konstantin Kouptsov, New York, USA, New York University

2006-PRESENT, Carvajal, Alexander, Bogotá, Columbia, Universidad Nacional de Colombia