Belinfante, J. G., B. Kolman, and H. A. Smith, “An Introduction to Lie Groups and Lie Algebras with Applications”,SIAM Review, 8 (Jan., 1966) No. 1, 11–46.
Borrego, J. T., H. Cohen, and E. E. DeVun, “Uniquely Representable Semigroups on the Two-Cell”,Pac. J. of Math., to appear.
Borrego, J. T., H. Cohen, and E. E. DeVun, “Uniquely Representable Semigroups II”,Pac. J. of Math., to appear.
Brown, D. R. and M. Friedberg, “Linear Representations of Certain Compact Semigroups,” to appear.
Hildebrant, J. S., “On uniquely divisible semigroups on the two-cell”,Pac. J. Math., 23 (1967), 91–95.
Hofmann, K. H. and P. S. Mostert, Elements of Compact Semigroups, C. E. Merrill Books, Columbus, Ohio (1966).