Vlasenko, I. Y. “Topological Properties of Periodic Components of <em class="a-Plus-plus">A</Em&gt;-Diffeomorphisms”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 54, no. 8, Aug. 2002, pp. 1031-4, https://umj.imath.kiev.ua/index.php/umj/article/view/4144.