An Outline of Set Theory
A volume in the series Problem Books in Mathematics
James M. Henle
Springer-Verlag, New York: 1986
Paperback. 145 pages. ISBN 0-387-96368-5 LCCN 86-013943
Recreations in Logic
D. G. Wells
Dover Publications, New York: 1979
Paperback. 55 pages. ISBN 0-486-23895-4 LCCN 79-51882