American Scientist 81 

 - New York  Sigma  Jul./Ago. 1993 
 - 404 
 - 20100310 
 - American Scientist  81 .
<br/><br/><label>ISSN: </label>1679-656X 
<br/><br/><label>Dewey Class. No.: </label>AMS 2010  / 2010