Are we alone  The Possibility of Extra-Terrestrial Civilizations  English 
Robert T Rood & James Trefil 
 - New York  Charles Scribners Sons  1981 
 - 262 
<br/><br/><label>ISBN: </label>068416826X 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Evolution and Phylogeny
<br/><br/><label>Dewey Class. No.: </label>999 ROO  / 10017