Nasyrova, V., S. Salmina, G. Kaigorodova, A. Mustafina, and G. Pyrkova. “Tax Competition Between Regions of Russia and Its Indicators”. Amazonia Investiga, Vol. 7, no. 14, June 2018, pp. 350-5, https://amazoniainvestiga.info/index.php/amazonia/article/view/528.