- Famous Problems of Mathematics, Solved and Unsolved Problems From Antiquity to Modern Times by Heinrich ; Hofstadter, Beatrice Kevitt [ed.] ; Komm, Horace [ed.] Tietze,  1966
 - Teyku : The Unsolved Problem in the Babylonian Talmus by Louis Jacobs,  1981
 - Tomorrow's Math: Unsolved Problems for the Amateur by Charles Stanley Ogilvy,  1972-02
 - Unsolved Problems in the Bibliography of J -J Rousseau (The Sandars Lectures in Bibliography) by R. A. Leigh,  1990-09-28
 - Unsolved Problems of the Milky Way 
 - Colour : Unsolved Problem of the West by Dr. Ben J. Marais,  1900
 - Sequences of numbers involved in unsolved problems by Florentin Smarandache,  2006-06-15
 - DR. GRANT'S SYSTEM OF RAILING SPIRAL STAIRS. THIS HITHERTO UNSOLVED PROBLEM SOLVED. THE SOLUTION IS EXCEEDINGLY SIMPLE. A FEW REMARKS ON THE TANGENT SYSTEM ARE ADDED. by C. C. Grant,  1911
 - Unsolved Problems Concerning Lattice Points (Research notes in mathematics) by Joseph Hammer,  1977-09-27
 - The Unsolved Problem: What Shall Be Done with the Liquor Traffic? by R D. Harper,  2010-05-25
 - Earth Rotation: Solved and Unsolved Problems (NATO Science Series C: (closed)) 
 - Unsolved Problems in Intuitive Mathematics (Mechanical Engineering (Springer-Verlag Telos Hardcover)) by Richard K. Guy,  1994-01
 - Solved and Unsolved Problems in Number Theory (CHEL/297) by Daniel Shanks,  2002-06
 - Teyku: The Unsolved Problem in the Babylonian Talmud : A Study in the Literary Analysis and Form of the Talmudic Argument by Louis Jacobs,  1981-10
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