Physical science today/ 
Isaac Asimov et al. 
 - Del Man, California:  CRM Books,  1973. 
 - 637 p.:  ill.,(part col.).;  27 cm. 
<br/><br/>p. 604-608. 
<br/><br/><label>ISBN: </label>0876651368 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Physics.<br/>Astronomy.<br/>Chemistry, Physical and theoretical.