1. Behrens, E.A.: Unendliche quasi-einreihige Halbgruppen. Math. Ann. 155, 343–368 (1964).
2. Behrens, E.A.: Partially ordered completely simple semigroups. J. of Algebra, to appear.
3. Behrens, E.A.: D-arithmetic prime rings. Math. Reports, McMaster University, Hamilton, Ont., vol. 2, no. 24 (1970).
4. Behrens, E. A.: The arithmetics of the quasi-uniserial semigroups without zero. To appear.
5. Behrens, E.A.: Theory of Rings. New York, Academic Press, to appear.