ProblemsJohn P. Hoyt, Mark Kantrowitz, M. S. Klamkin, Thomas S. Ferguson, Thomas P. Dence, Kenneth A. Brown, Jr., Ruth Koelle, James Propp, Vania D. Mascioni, James S. Robertson, John M. H. Olmsted and John Putz · Mathematics Magazine · 1983

Automatic Completely-Simple SemigroupsC. M. Campbell; E. F. Robertson; M. Ruškuc; R. M. Thomas · 2002

Fibonacci semigroupsColin M. Campbell; Edmund F. Robertson; Nikola Ruškuc; Richard M. Thomas · Journal of Pure and Applied Algebra · 1994

Automatic semigroupsColin M. Campbell; Edmund F. Robertson; Nikola Ruškuc; Richard M. Thomas · 2001

Problem DepartmentPaul D. Thomas, Earl V. Greer, N. A. Court, V. Thebault, LeRoy Pietsch, A. Sisk, Nev. R. Mind, Joseph S. Guerin, M. S. Robertson, E. P. Starke, H. J. Zimmerberg, Howard D. Grossman, P. T. Thomas, Howard D. Grossman, Walter B. Clarke and Howard Eves · National Mathematics Magazine · 1944

Problem DepartmentWalter B. Clarke, Daniel Arany, Paul D. Thomas, John H. Giese, D. L. MacKay, David L. Bowman, H. T. R. Aude, W. V. Parker, R. F. Rinehart, M. S. Robertson and Alice M. H'Doubler · National Mathematics Magazine · 1942

Problem DepartmentNelson Robinson, E. P. Starke, M. S. Robertson, C. N. Mills, Paul D. Thomas, Ray Hassler, Alice M. H'Doubler, Robert V. Sweeney, N. A. Court, Clarence M. Ablow, James F. Callicott, W. V. Parker, V. Thebault, Howard D. Grossman and D. L. MacKay · National Mathematics Magazine · 1942

Reidemeister-Schreier type rewriting for semigroupsC. M. Campbell; E. F. Robertson; N. Ruškuc; R. M. Thomas · Semigroup Forum · 1995