Dooms, A., & Jespers, E. (2004). Generators for a Subgroup of Finite Index in the Unit Group of an Integral Semigroup Ring. Journal of Group Theory, 7, 543-553. http://www.reference-global.com/doi/abs/10.1515/jgth.2004.7.4.543

@article{85fb8fdc03c54baf87192aaed4ac6509,
title = "Generators for a Subgroup of Finite Index in the Unit Group of an Integral Semigroup Ring",
abstract = "Let S be a finite semigroup. The paper under review studies units of the semigroup ring ZS over the integers. Suppose QS does not have an epimorphic image which is a 2×2 matrix ring over Q or a quadratic imaginary extension of Q or a noncommutative division ring. Assume that if G is a maximal subgroup of S with QG and QS having isomorphic noncommutative simple image, then G has no non-abelian fixed-point free homomorphic image. Let U be the group generated by Bass cyclic units, bicyclic units, or units of the form 1+x where x is running through some finite multiplicatively closed set of additive generators of the radical of ZS. Then, U is of finite index in the unit group of ZS.",
author = "Ann Dooms and Eric Jespers",
note = "J. Group Theory 7 (2004), no. 4, 543--553.",
year = "2004",
language = "English",
volume = "7",
pages = "543--553",
journal = "Journal of Group Theory",
issn = "1433-5883",
publisher = "Walter de Gruyter GmbH",
}