Clarke, George Robin. <br/><br/>
The study of soil in the field / 
by G. R. Clarke assisted by Philip Beckett. 
 - 5th ed. 
 - Oxford:  Clarendon,  1971. 
 - xi, 145 p. :  ill. ;  23 cm. 
<br/><br/>Bibliography: p. 139-141. 
<br/><br/><label>ISBN: </label>0198541171 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Soil surveys