SCHMITZ , H / SOMMER , M / WALTER , S . <br/><br/>
ANIMAL TRACTION IN RAINFED AGRICULTURE IN AFRICA AND SOUTH AMERICA .  Determinants and Experiences 
HERIBERT SCHMITZ / MATHIAS SOMMER / SABINE WALTER 
 - BRAUNSCHWRIG  VIEWEG  1991 
 - 311p.:ill.;  pbk 
<br/><br/><label>ISBN: </label>3528020598 
<br/><br/><label>LC Class. No.: </label>S760 .S2 1991