| May 2011 | Thomas Weigel, Dipartimento di Matematica e Applicazioni, Università degli Studi di Milano-Bicocca, Milano, Italy (3 weeks) |
| March 2011 | Mahir Can, Department of Mathematics, Tulane University, New Orleans, Louisiana (2 days) |
| May 2009 | Sarah Witherspoon, Department of Mathematics, Texas A&M University, College Station, Texas (4 days) |
| March 2008 | Mathematical Sciences Research Institute, Berkeley, California (5 days) |
| March 2007 | Randall Holmes, Department of Mathematics and Statistics, Auburn University, Auburn, Alabama (1 day) |
| May 2003 | Thorsten Holm, Department of Mathematics, Otto-von-Guericke University of Magdeburg, Germany (1 week) |
| July/August 1999 | Claus Michael Ringel, Sonderforschungsbereich 343 “Discrete Structures in Mathematics”, University of Bielefeld, Germany (1 & 1/2 months) |
| April 1998 - July 1998 | Karin Erdmann, Mathematical Institute, University of Oxford, Oxford, England (3 months) |
| March 1998 | Daniel Nakano, Department of Mathematics and Statistics, Utah State University, Logan, Utah (4 weeks) |
| February 1997 - April 1997 | Daniel Nakano, Department of Mathematics and Statistics, Utah State University, Logan, Utah (3 months) |
| January 1997 | Karin Erdmann, Mathematical Institute, University of Oxford, Oxford, England (2 weeks) |
| October 1996 - December 1996 | Lee Klingler, Department of Mathematical Sciences, Florida Atlantic University, Boca Raton, Florida (3 months) |
| March 1995 | Daniel Nakano, Department of Mathematics, Northwestern University, Evanston, Illinois (1 week) |
| February/March 1993 | Allen Bell, Department of Mathematical Sciences, University of Wisconsin, Milwaukee, Wisconsin (4 weeks) |
| November 1992 | Joseph Ferrar, Department of Mathematics, The Ohio State University, Columbus, Ohio (1 week) |
| November 1992 | Frank Röhl, Department of Mathematics, The University of Alabama, Tuscaloosa, Alabama (1 week) |
| March 1992 | Daniel Nakano, Department of Mathematics, Northwestern University, Evanston, Illinois (1 week) |
| March 1992 | Frank Röhl, Department of Mathematics, The University of Alabama, Tuscaloosa, Alabama (1 week) |
| February 1992 | Georgia Benkart, Department of Mathematics, University of Wisconsin, Madison, Wisconsin (4 weeks) |