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Submitted on: 17 September 2012.
Revised on: 01 November 2012.
Accepted on: 14 November 2012.
___________________AMERICAN NATURALIST---UNIV CHICAGO PRESS
Submitted on: 05 December 1999.
Revised on: 12 February 2000.
Accepted on: 15 March 2000.
___________________AMERICAN NATURALIST---UNIV CHICAGO PRESS
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Submitted on: 16 July 2006.
Revised on: 02 October 2006.
Accepted on: 12 November 2006.
___________________AMERICAN NATURALIST---UNIV CHICAGO PRESS
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