1. June-July 2001, Cytel Pvt. Ltd., Boston, USA.
2.
18th June- 3rd July
2005, Indian Statistical Institute, Kolkata.
3.
1st September 2008 - 30th April 2009,
Department of Statistics, University of Michigan, Ann Arbor, USA.
2.
21st March- 26th March
2011, Indian Statistical Institute, Kolkata.