TY JOUR TI Bismuth-containing low-melting glasses and the structural state of bismuth in them KW bismuth-containing borate glasses KW thermal expansion KW initial softening point KW structural bismuth oxygen group KW valence state of bismuth JO Technique and technology of silicates AU Bobkova, N.M. PY 2013 IS 20 PB Individual Entrepreneur Svetlana Vasilievna Samchenko