- Prime Obsession: Bernhard Riemann & the Greatest Unsolved Problem by John Derbyshire, 23 April, 2003
- Ball Lightning: An Unsolved Problem in Atmospheric Physics by Mark Stenhoff, March, 2000
- The Millennium Problems: The Seven Greatest Unsolved Mathematical Puzzles of Our Time by Keith J. Devlin, 15 October, 2002
- Unsolved Problems in Astrophysics by John N. Bahcall, Jeremiah P. Ostriker, 17 January, 1997
- The Riemann Hypothesis: The Greatest Unsolved Problem in Mathematics by Karl Sabbagh, April, 2003
- Erdos on Graphs: His Legacy of Unsolved Problems by Fan Chung, Ron Graham, et all July, 1998
- The Five Biggest Unsolved Problems in Science by Arthur W. Wiggins, Charles M. Wynn, August, 2003
- Old and New Unsolved Problems in Plane Geometry and Number Theory by Victor Klee, Stan Wagon, September, 1996
- Unsolved Problems in Number Theory (Problem Books in Mathematics) by Richard K. Guy, August, 1997
- Tomorrow's Math: Unsolved Problems for the Amateur by Charles Stanley Ogilvy, April, 1992
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