Robertson, Gerald C. <br/><br/>
An APL manual for the school of agricultural economics and extension education. 

 - Ontario :  University of Grulph,  1973. 
 - Reprint no. 29 .
<br/><br/> Computer manual. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Agriculture.<br/>Agricultural equipment.