Grätzer, George A..
Train your brain: a year's worth of puzzles /
George Grätzer ; translated by Tom Artin 
. - Boca Raton : A.K. Peters/CRC Press,  2011 
. - xviii, 235 p.  ill.  23 cm. 
<br/><label>  ISBN: </label>978-1-56881-710-1