Sumaruk, T. P., and P. V. Sumaruk. “Dependence of the Velocity Changes of Secular Variations on the Position of Observatory and Time”. Geofizicheskiy Zhurnal 43, no. 3 (October 5, 2021): 181–192. Accessed April 19, 2024. https://journals.uran.ua/geofizicheskiy/article/view/236388.