Condra, Geo. E.  1869-1958. <br/><br/>
Correlation of the Big Blue series in Nebraska, 
by G. E. Condra and J. E. Upp. 
 - [Lincoln]  Printed by authority of the state of Nebraska,  1931. 
 - 74, [2] p. incl. illus., map, tables.  25 cm. 
 - Nebraska.  Geological survey.  Bulletin 6, second ser. .
<br/><br/> At head of title: University of Nebraska. 
<br/><br/>"Annotated bibliography of the Big Blue series": p. 68-74. 
<br/><br/><label>LCCN: </label>gs 32000041  
<br/><br/><label>Subjects--Topical Terms: </label><br/>Geology--Nebraska.<br/>Geology, Stratigraphic--Permian.
<br/><br/><label>LC Class. No.: </label>QE135  / .A4 no. 6