Wallis, W. D. <br/><br/>
Combinatorics  ; room squares, sum-free sets, hadamard matrices / 

 - Berlin:  Springer-Verlag,  1972 
 - vi, 508p. 
 - Lecture notes in Mathematics   292 .
<br/><br/><label>Dewey Class. No.: </label>511.6  / W214.CR