April 1978, Cumberland Lodge, Windsor, U.K.
May 1980, St. Trudo Abbey at Male, Brugge, Belgium.
November 1981, Woudschoten, Zeist, The Netherlands.
September 1983, Abbaye de Royaumont, Asnieres-sur-Oise, France.
September 1985, Haus Lerbach, Bergisch-Gladbach, Germany.
September 1987, University of Pavia, Italy.
September 1989, Kartause Ittingen, Warth, Switzerland.
October 1991, Centre de Reunion des Pensieres, Fondation Marcel Merieux, Annecy, France.
October 1993, European Cultural Centre, Delphi, Greece.
September 1995, Queens’ College, Cambridge, U.K.
September 1997, Bad Deutsch-Altenberg, Austria.
September 1999, Vidago, Portugal.
September 2001, Woudschoten, Zeist, The Netherlands.
September 2003, Podebrady, Czech Republic.
September 2005, Olso, Norway.
September 2007, Perugia Italy