Near-rings generated by R -modules. Clay, James R., Kautschitsch, Hermann (1993) Mathematica Pannonica
Notes on slender prime rings Robert El Bashir, Tomáš Kepka (1996) Commentationes Mathematicae Universitatis Carolinae If R is a prime ring such that R is not completely reducible and the additive group R ( + ) is not complete, then R is slender.