Blackstock, Paul W. <br/><br/>
The secret road to World War Two :  Soviet versus Western intelligence 1921-1939, 
[by] Paul W. Blackstock. 
 - Chicago :  Quadrangle Books,  1969. 
 - 384 p. ;  25 cm. 
<br/><br/><label>Subjects--Index Terms: </label>Intelligence service -- Soviet Union. Secret service -- Soviet Union.