Comparing the valence control of 'PR' and 'TB' in zirconia by co-doping effect - Carvalho, J. M.; Brito, Hermi Felinto de; Rodrigues, Lucas Carvalho Veloso; Nunes, Luiz Antônio de Oliveira; Lastusaari, Mika; Laamanen, Taneli; Hölsä, Jorma (International Conference on the Physics of Optical Materials and Devices - ICOM, 2012)