Klass, Philip J. <br/><br/>
Secret sentries in space / 
by Philip J. Klass. 
 - New York :  Random House,  1971. 
 - xvi, 236 p.:  ill. 
<br/><br/><label>ISBN: </label>0394469720 
<br/><br/><label>LCCN: </label>88901209     
<br/><br/><label>Subjects--Topical Terms: </label><br/>Astronautics, Military--United States.<br/>Astronautics, Military--Russia.
<br/><br/><label>Subjects--Geographic Terms: </label><br/>Earth--Photographs from space.