TY JOUR TI Topical issues of tax and legal regulation of the digital economy KW digital economy KW tax and legal regulation KW digital tax KW digital taxpayer presence KW digital transactions KW tax administration KW taxation of operations using cryptocurrency JO Legal Science and Practice: Journal of Nizhny Novgorod Academy of the Ministry of Internal Affairs of Russia AU Kuchyerov, I.I. PY 2019 IS 2019 PB Nizhny Novgorod Academy of the Ministry of the Interior of Russia