TY JOUR TI REVIEW OF THEORETICAL APPROACHES TO DETERMINING THE COMPETITIVENESS OF A FIRM KW competition KW competitiveness KW firm economics KW competitiveness criteria KW digitalization KW entrepreneurship KW competitive advantage KW competitive potential KW competitive products KW efficiency KW enterprise flexibility JO Trade, service, food industry AU Churaeva, A.V. PY 2021 IS 1 PB Siberian Federal University