Challenging problems in algebra /

by Posamentier, Alfred S
Published 1996

Problems in group theory /

by Dixon, John D
Published 2007

The stanford mathematics problem book : with hints and solutions /

by Pólya, George, 1887-1985
Published 2009

Mathematical conversations : Multicolor problems, Problems in the theory of numbers, and Random walks /

by Dynkin, E. B (Evgeniĭ Borisovich), 1924-2014, Dynkin, E. B (Evgeniĭ Borisovich), 1924-2014
Published 2006

Attacking trigonometry problems /

by Kahn, David S.
Published 2015

Mathematical quickies : 270 stimulating problems with solutions /

by Trigg, Charles W, Trigg, Charles W
Published 1985