| J. Stern , Ecole Normale Supérieure , Paris, France, May 1 - June 1, 1990 |
| M. Boffa , Universite de l'Etat a Mons, , Belgium, May 1 - June 1, 1990 |
| R. Chuaqui , University Catholica de Chile, Santiago, Chile, May 1 - June 1, 1990 |
| D. Follesdal , Institute for Advanced Study, Berlin, Germany, May 1 - June 1, 1990 |
| I. Hacking , University of Toronto, Toronto, Canada, May 1 - June 1, 1990 |
| D. Kurepa , Belgrade University, Belgrade, Yugoslavia, May 1 - June 1, 1990 |
| J. Moravscick , Stanford University, Stanford, USA, May 1 - June 1, 1990 |
| A. Edalat , Imperial College London, London, UK, May 1 - June 1, 1990 |
| Freydoon Mansouri , University of Cincinnati, Cincinnati, USA, April 20 - May 20, 1990 |
| S. Apikyan , Yerevan Physics Institute, Yerevan, Republic of Armenia, Jan. 1, 1990 |
| M. Mortazavi , University of California, Berkeley, Berkeley, USA, Jan. 1, 1990 |
| Yavuz Nutku , Tubitak Marmara Research Center, Gebze, Turkey, Jan. 1, 1990 |
| Ruben Manvelyan , Yerevan Physics Institute, Yerevan, Republic of Armenia, Jan. 1, 1990 |
| V. Kosygin , Moscow State University, Moscow, Russia, Jan. 1, 1990 |
| A. Yusuf , Quaid-e-Azam University, Islamabad, Pakistan, Jan. 1, 1990 |
| A. Pyartli , Ivanovo State Power University (ISPU), Ivanovo, Russia, Jan. 1, 1990 |
| G. Shabbir , Quaid-e-Azam University, Islamabad, Pakistan, Jan. 1, 1990 |
| A. Shcherbakov , Moscow Bio-Electrical Research Institute, Moscow, Russia, Jan. 1, 1990 |
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