Assessment of potential radiological health effects from radon in natural gas / 
Raymond H. Johnson...[et al.] 
 - Washington, D.C. :  U.S. Environmental Protection Agency,  1973 
 - ix, 60 p. :  ill. ;  28 cm. 
<br/><br/> November 1973  EPA-520/1-73-004 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Natural gas--Geology<br/>Coalbed methane
<br/><br/><label>Dewey Class. No.: </label>553.285