Mark E. Villiger <br/><br/>
Customary international law and treaties : a manual on the theory and practice of the interrelation of sources 

 - 2nd rev. ed. 
 - Hague  Kluwer Law International  1997 
 - 346 
<br/><br/><label>LC Class. No.: </label>KZ 1277  / VIL 1997