Nezar E. Ali, and Azher A. Mohammad. “Stability Conditions of Limit Cycle for Gompertz Autoregressive Model”. Tikrit Journal of Pure Science 28, no. 2 (April 27, 2023): 129–134. Accessed November 13, 2024. http://tjps.tu.edu.iq/index.php/tjps/article/view/1348.