TY JOUR TI On the Precursors of Solar Flares in September 2017 KW Sun KW x-rays KW flares KW precursor JO Infocommunications and Radio Technologies AU Volvach, A.E. AU Kogan, L.P. AU Volvach, L.N. AU Yakubovskaya, I.V. PY 2023 IS 6 PB Federal State Educational Institution of Higher Education Sevastopol State University