Pacific Northwest National Laboratory, USA

Hanyang University, Seoul, S. Korea

University of Texas at Austin, USA

University of Pennsylvania, Philadephia, USA

University of Adelaide, Adelaide, Australia

University of Cincinnati, Cincinnati, Ohaio, USA

University of Colorado Boulder, USA

University of Naples "Federico II", Naples, Italy

Universidad de Guanajuato, Guanajuato, Mexico

London School of Economics and Political Science, London, UK

Transylvania University of Brasov, Brasov, Romania