TY JOUR TI STEROL CONTENT IN THE TISSUES OF BIRCH (BETULA PENDULA) AND POPLAR (PUPOLUS TREMULA) KW ethers KW sterols KW glycosides KW annual cycle KW fatty acid KW oleic acid KW linoleic acid JO Bulletin of KSAU AU Devyatlovskaya, A.N. AU Zhuravlyeva, L.N. PY 2013 IS PB Krasnoyarsk State Agrarian University