02/2006 University of Dundee, Ramsey Tax in Imperfect Competition; 10/2005 University of St Andrews and University of Edinburgh, Ramsey Tax in Imperfect Competition; 02/2005, Heriot Watt University, Ramsey Tax in Imperfect Competition; 12/2004, Heriot-Watt University, Heterogeneous expectations, dynamics, and stability of markets; 12/2003 European University Institute, Florence, Italy, Imperfectly Competitive Dynamics With Underemployment; 11/2003 European University Institute, Florence, Italy Heterogeneous expectations, dynamics, and stability of markets; 01/2003 Heriot-Watt University, Heterogeneous expectations, dynamics, and stability of markets; 10/2002 University of Manchester and University of St. Andrews, Heterogeneous expectations, dynamics, and stability of markets