TY JOUR TI IMPACT OF VALUE ADDED TAX ON CHOICE TAX SYSTEMS FOR SMALL ENTITIES ENTREPRENEURSHIP KW tax system KW small business KW value added tax KW financial result JO Modern Technologies and Scientific and Technological Progress AU Zarubina, Y.V. AU Zayceva, E.V. PY 2026 IS 2026 PB Federal State Funded Educational Establishment of Higher Education «Angarsk State Technical University»