Tom Tietenberg is the Mitchell Family Professor of Economics, Emeritus at Colby College, Maine, USA.

Lynne Lewis is Elmer W. Campbell Professor of Economics at Bates College, Maine, USA.

Tom Tietenberg is the Mitchell Family Professor of Economics, Emeritus at Colby College, Maine, USA.

Lynne Lewis is Elmer W. Campbell Professor of Economics at Bates College, Maine, USA.