Cottrell, K.W. <br/><br/>
Asphalt and related bitumens in 1922. 

 - Washington, D.C.  Government Printing Office  1923 
 - pp. 7-13 
<br/><br/> Impreso 
<br/><br/><br/>Ingles 
<br/><br/><label>Subjects--Topical Terms: </label><br/>MINERIA