Sys, C. <br/><br/>
Land evaluation  : principles in land evaluation and crop production calculations 
/ C. Sys,...E. Van Ranst,...Delaveye,... 
. - Brussels  : General administration for development cooperation, 1991
. - 273p.  ; 30Cm. 
 - Agricultural publication  7 .
<br/><br/><label>Universal Decimal Class. No.: </label>631. 48.