Longo, Frank, <br/><br/>
Second-Degree Brown Belt Sudoku : 

 -  Sterling Publishing Company, Inc.,  2005. 
 - 196 pages 
<br/><br/><label>ISBN: </label>9781402737169 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Games & Activities.
<br/><br/><label>Dewey Class. No.: </label>793.74  / LON