Afanasev, Aleksandr Alekseevich, et al. “Synchronization of Processes Related to Economic Activity With Stages of Development of Spatially-Organized Systems”. International Journal of Economics and Financial Issues, vol. 5, no. 3S, Dec. 2015, pp. 121-4, https://mail.econjournals.com/index.php/ijefi/article/view/1700.