TY JOUR TI THE IMPROVEMENT OF THE TANNING EXTRACT PRODUCTION FROM THE CONIFEROUS BARK WITH THE USE OF ALKALINE EXTRACTANTS KW bark KW water-alkaline extracts KW good quality KW sulphitation KW ultrafiltration JO Bulletin of KSAU AU Eremenko, O.N. AU Mishura, P.V. AU Ryazanova, T.V. AU Tok, M.V. PY 2015 IS PB Krasnoyarsk State Agrarian University