Luminescent hourglass inclusion (LHI). Europium coordination compounds trapped in 'K IND.2'S'O IND.4' crystal - Serra, Osvaldo Antônio; Nassar, Eduardo José; Kodaira, C A; Neri, C R; Calefi, Paulo Sérgio; Rosa, Ieda Lúcia Viana (International School on Excited States of Transition Elements, 1997)