Procedure to retrieve the paper.
(a) The document is at http://ifs.plants.ox.ac.uk/tune/tune96/contents.html Please read further
(b) after opening the page, place your cursor on the document "Studies on Duck Production in the Mekong Delta, Vietnam" (page 104), click with the right button of the mouse for the menu to save it.
(c) The paper is stored in Adobe PDF format. To read the saved document,  you need the software Acrobat Reader. If you do not have this software, it is available free of charge for downloading at http://www.adobe.com/supportservice/custsupport/download.html