Ryan, Jay, <br/><br/>
Cycles :  an introduction to astronomy and time / 
by Jay Ryan. 
 - 32 páginas :  ilustraciones 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Astronomía.
<br/><br/><label>Dewey Class. No.: </label>520  / R988c 1997