Sudoku on the flip side :  conceptis puzzles 

 - New York :  Sterling Publishing Co., Inc.,  c2006 
 - 320 p. :  ill. ;  20 cm. 
<br/><br/> "Over 150 puzzles" -- Cover 
<br/><br/><label>ISBN: </label>9781402737114 1402737114 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Games<br/>Sudoku