Tchad (1) Instruction and study (1) Intercession (1) Development (1) Pastoral systems (1) Water (1) Vision (1) Time (1) Production (Economic theory) (1) Hydraulics (1) Hand (1) Goal (Psychology) (1) Foreign exchange (1) Experience (1) Evidence (1) Building (1) Agricultural systems (1) Space (1) Valuation (1) Movements (1) Technological innovations (1) Teachings (1) Rating of (1) Practice (1) International cooperation (1) Evaluation (1) Sistemas agrícolas (1) Evaluación (1) Cambio exterior (1) Manos (1)