Sullivan, Walter <br/><br/>
We are not alone   : The search for intelligent life on other worlds 

 - New York:  Mc Graw-Hill  1966 
 - xi, 325p. ; 21 cm. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Astrofísica y Astronomía Descriptiva<br/>Vida extraterrestre<br/>extraterrestrial life