Read, Charles B.  1907-1979 <br/><br/>
Upper paleozoic floral zones and floral provinces of the United States / 
by Charles B. Read and Sergius H. Mamay. 
 -- Washington :   United States Government Printing Office,   1964 
 - 35 p., [19] h. de lam. -- 
 (Geological Survey Professional Paper  ;  454-K).
<br/><br/><label>Subjects--Topical Terms: </label><br/>Estados Unidos<br/>Paleobotánica
<br/><br/><label>Universal Decimal Class. No.: </label>561(73)