“…Further study of the hidden Chua attractors and their observation in physical experiments can be found, e.g. in Chen et al, 2015a;Bao et al, 2015a;Chen et al, 2015c,b;Zelinka, 2016;Bao et al, 2016;Menacer et al, 2016;Chen et al, 2017a;Rocha et al, 2017;Hlavacka & Guzan, 2017]. The synchronization of Chua circuits with hidden attractors is discussed, e.g.…”