1. CIRAD, UR AIDA Montpellier cedex 5, France
2. CIRAD, UR TETIS Montpellier cedex 5, France
3. MAF, DALaM, PAFO Xieng Khouang, Phonsavanh, Lao PDR
4. Consultant, Vientiane, Lao PDR
5. CIRAD, UR GECO, Montpellier cedex 5, France
6. IRD, UMR 220 GRED, Montpellier cedex 5, France