This writing inspired from paper by Jafari, Sprott, Golpayegani (2013) whereas they found 17 chaotic systems with chaotic flow without no-equilibrium. This paper indicate that all of the system happens to have cascade of period-doubling. In this paper, we found that this cascade of period-doubling can be obtained either from periodic solution of Hopf bifurcation or hidden attractor. Thus, we try to study these models to see if the periodic solution happens because of Hopf bifurcation or have hidden attractor since the beginning.