“…Consequently, the Fishing principle has provided mathematicians with a universal tool for analytically proving the existence of homoclinic orbits in a number of well-known dynamical systems. Last, but not least, the notion of hidden attractors and the development of new mathematical methods for investigating such attractors in classic dynamical systems [Leonov & Kuznetsov, 2013;Leonov et al, 2015b;Kuznetsov et al, 2018] have attracted a great deal of interest from researchers in various fields, especially mathematicians, engineers, and physicists [Bragin et al, 2011;Sharma et al, 2015aSharma et al, , 2015bDudkowski et al, 2016;Chen et al, 2017;Stankevich et al, 2017]. Largely due to the discovery of hidden attractors in dynamical systems, Gennady Leonov and his former doctoral student Nikolay V. Kuznetsov were proclaimed as the Highly Cited Researchers in the Russian Federation twice over two consecutive years (2016-2017) by Clarivate Analytics.…”