“…More recently, in 2013 Yu and Wang, introduced a new three dimensional chaotic system with a complicated structure which we write here in order to have a self contained paper ẋ =a(y − x), ẏ =bx − cxz, ż = sinh(xy) − dz, (1) with a, b, c, d ∈ R. The above system has a nonpolynomial structure, considered by the authors in a previous work [15]. System (1) possesses a new strange attractor with four wings [16]. A nice analysis of the complicated structure of a four wing system appears in a e-mail: abimael.bengochea@itam.mx b e-mail: alechung@xanum.uam.mx c e-mail: ernesto.perez@itam.mx (corresponding author) [11] and also in [14].…”