Magneto optical studies of valence instability in europium and terbium phosphors - Rodrigues, Lucas Carvalho Veloso; Hölsa, Jorma; Brito, Hermi Felinto de; Marysko, Miroslav; Matos, Jivaldo do Rosário; Paturi, Petriina; Rodrigues, Rodrigo Vieira; Lastusaari, Mika (Journal of Luminescence, 2016)