TY JOUR TI Optimization of value chain management based on a supplier audit system KW contractor audit KW value chains KW procurement management KW supplier reliability assessment KW quality control KW risk management JO Bulletin of scientific research results AU Kazanskaya, L.F. AU Fedorova, A.N. AU Makarov, Y.I. AU Latypova, i.A. PY 2026 IS 2026 PB FSBEI HE "Emperor Alexander I St. Petersburg State Transport University"