Unsolved Problems in Number Theory (Unsolved Problems in Intuitive Mathematics)

Problem Books in Mathematics: Unsolved Problems in Number Theory by Richard...

Unsolved Problems in Number Theory (Problem Books in Mathematics), Guy, Richard,

Ams Chelsea Publishing Ser.: Solved and Unsolved Problems in Number Theory by...

Field Theory and Its Classical Problems (Carus Mathematical Monographs ; No. 19)

Old and New Unsolved Problems in Plane Geometry and Number Theory (Dolciani ...

Classical Mathematical Physics: Dynamical Systems and Field Theories

The Millennium Problems: The Seven Greatest Unsolved Mathematical Puzzles of...