Britannica <br/><br/>
The Young Children's Encyclopedia :  Volume 11 / N-O / 
Britannica. 
 - USA :  Encyclopedia Britannica Inc,  1985. 
 - 159 
 - The Young Children's Encyclopedia .
<br/><br/> General information for young children beginning with the letters N-O. 
<br/><br/><label>ISBN: </label>0852294263 
<br/><br/><label>Subjects--Topical Terms: </label><br/>General information- N-O -juvenile