Kurdachenko, L. A., Petrenko, B. V., & Subbotin, I. Y. (1997). On complementability of certain generalized hypercenters in Artinian modules. Ukrains’kyi Matematychnyi Zhurnal, 49(11), 1548–1552. https://umj.imath.kiev.ua/index.php/umj/article/view/5154