Zeeman, E. C. <br/><br/>
Seminar on combinatorial topology.  Chap. 8,  Embedding and unknotting. 

 - Bures-sur-Yvette:  I.H.E.S.,  1966. 
 - 60 p.: 
<br/><br/><label>Dewey Class. No.: </label>514.22   /