Interesting books
- Lovasz Pelikan
Vesztergombi Discrete Mathematics ,
- Andreescu T. Problems
in Real Analysis - Advanced Calculus on the Real Axis (Springer 2009)
,
- Andreescu Andrica
Cucurezeanu Diophantine Equations,
- Andreescu Andrica Feng
104 Number Theory Problems,
- Halmos Problems for
Mathematicians,
- Souza, Silva - Berkeley problems in Mathematics