Guidelines for soil description 

 - Fourth edition 
 - Rome :  Food and Agriculture Organisation,  2006 
 - x, 97 p. :  ill. ;  25 cm. 
<br/><br/>Includes bibliographical references (p.85-86) 
<br/><br/><label>ISBN: </label>9251055211 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Soil formation