Report Number: CS-TR-72-292
Institution: Stanford University, Department of Computer Science
Title: Selected combinatorial research problems.
Author: Chvatal, Vaclav
Author: Klarner, David A.
Author: Knuth, Donald E.
Date: June 1972
Abstract: Thirty-seven research problems are described, covering a wide range of combinatorial topics. Unlike Hilbert's problems, most of these are not especially famous and they might be "do-able" in the next few years. (Problems 1-16 were contributed by Klarner, 17-26 by Chvatal, 27-37 by Knuth. All cash awards are Chvatal's responsibility.)
http://i.stanford.edu/pub/cstr/reports/cs/tr/72/292/CS-TR-72-292.pdf