Luminescence study of the layered niobate K'Ca IND. 2''Nb IND. 3''O IND. 10' doped with 'Eu POT. 3+'and 'La POT. 3+' ions - Brito, Hermi Felinto de; Constantino, Vera Regina Leopoldo; Bizeto, Marcos Augusto (Rare Earth Research Conference, 1999)