Nowadays, one of the most studied phenomena is chaos into the nonlinear dynamical systems.
A novel chaotic system without equilibrium: Dynamics, synchronization, and circuit realization
2017Azar A.T.Gerodimos N.A.JournalMunoz-Pacheco J.M.Ouannas A.Pham V.-T.Radwan A.G.Tombras G.S.Vaidyanathan S.Volos C.
A few special chaotic systems without unstable equilibrium points have been investigated recently
Fractional-order and memristive nonlinear systems: Advances and applications
Chaotic systems are nonlinear dynamical systems which are sensitive to initial conditions, topologically mixing, and with dense periodic orbits