(In addition to numerous invited lectures at conferences, etc.)
| 1970 | Three months at the University of Ife, Nigeria. |
| 1974 | One month at International Centre for Theoretical Physics, Trieste, Italy. |
| 1975 | One month at Max-Planck Centre for Molecular Beam Research, Göttingen, Germany. |
| 1976 | Three months at the Indian Institute of Science, Bangalore. |
| 1980 | Six weeks at the Les Houches Summer School, France. |
| 1980-81 | Kramers Professor of Physics at the University of Utrecht, The Netherlands. |
| 1980 | Troisième Cycle de la Suisse Romande Lecturer in Theoretical Physics at Geneva and Lausanne, Switzerland. |
| 1981 | Three weeks at the Les Houches Summer School, France. |
| 1983 | One month visiting Fellow at Australian National University, Canberra (Dept. of Applied Mathematics). |
| One month Erskine Visiting Fellow at University of Canterbury at Christchurch, New Zealand (Dept. of Electrical Engineering). | |
| 1985 | One month Visiting Lecturer at Institut Physique Nucléaire, Orsay, France. |
| One month Visiting Fellow at California Institute of Technology, USA. | |
| 1986-97 | Fellowship at Weizmann Institute, Rehovot, Israel (annual visits, one month each). |
| 1988 | One Month Visiting Lecturer at Department of Mathematics, University of Nice, France. |
| 1989 | Two weeks at Les Houches summer School, France . |
| 1993 | Two weeks as Director of School on Geometric Phases, ICTP Trieste, Italy |
| 1999- | Visiting Fellow, Technion, Haifa, Israel. |
| 1999 | Two months as Lorentz Professor, Leiden, The Netherlands. |
| 2004 | Lecturing at Summer School on Vortices at Cargese (Corsica). |
| 2006 | Lecturing at School on Wave Propagation at Cuernavaca (Mexico). |
| 2007 | One month as Solvay Professor, Université Libre, Brussels. |
| 2008 | One month as Distinguished Visiting Professor, ICTP Trieste |