Presented at AMS/MAA Meeting, San Diego, January 10, 2018
AMS/MAA Meeting, Boston, January, 2012
Bridges, July 28, 2011
University of Coimbra, Portugal, July 27, 2011
Presented at MAA-AMS Meeting
New Orleans, January 7, 2011
Presented at MAA-AMS Meeting, San Francisco, January 16, 2010
Presented at Gathering for Gardner 9,
Atlanta, March 25, 2010
Bridges, Banff, July 27, 2009
