Macdonald, Ray <br/><br/>
Chemistry of the subalkalic silicic obsidians /  by ..., Robert L. Smith and John E. Thomas 

 - Washington :  U. S. Govt. Print. Off.,  1992 
 - 214 p. 
 - United States. Geological Survey. Professional paper ;  no. 1523 .
<br/><br/><label>Subjects--Topical Terms: </label><br/>Obsidian--Composition
<br/><br/><label>LC Class. No.: </label>QE75 P9 no. 1523