TY JOUR TI KEY ELEMENTS OF BUSINESS MODELS OF THE LARGEST OIL AND GAS COMPANIES IN RUSSIA KW oil and gas industry KW oil and gas companies KW business model KW ESG KW Gazprom Neft KW Lukoil KW Rosneft KW Surgutneftegaz KW Tatneft KW NOVATEK JO Russian Journal of Management AU Umaev, M.O. AU Dadaev, R.M. PY 2025 IS 13 PB Publishing Center RIOR