Kirby, H.W. <br/><br/>
History, isotopes, recovery of Thorium  Th : Thorium : System number 44 
H.W. Kirby 
 - 8. ed. 
 -  1986, 1986 
 - XV, 233 S. : Ill., graph. Darst. 
<br/><br/><label>ISBN: </label>3540935320 0387935320 
<br/><br/><label>Universal Decimal Class. No.: </label>546+546.3