GILMER, R.; HEINZER, W. An Application of Jonsson Modules to Some Questions Concerning Proper Subrings. Mathematica Scandinavica, Berkeley, CA, United States, v. 70, p. 34–42, 1992. DOI: 10.7146/math.scand.a-12385. Disponível em: https://journals.msp.org/mscand/article/view/1263. Acesso em: 24 jul. 2026.