Submitted on: 11 March 2002.
Revised on: 12 June 2002.
Accepted on: 09 July 2002.
___________________AGRICULTURAL HISTORY---DUKE UNIV PRESS
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Submitted on: 11 September 1998.
Revised on: 05 December 1998.
Accepted on: 17 December 1998.
___________________AGRICULTURAL HISTORY---DUKE UNIV PRESS