Lecture Notes on Bayesian Estimation and Classification
《Lecture Notes on Bayesian Estimation and Classification》 · 第 367 页 · Section 12.2「Some Special Types of Locally Nilpotent Groups」，小节「Baer Groups and Gruenberg Groups」
A group is called a Gruenberg group if every cyclic subgroup is ascendant and a Baer group if every cyclic subgroup is subnormal.