WANTANA, N.; INSIRIPONG, S.; RUANGTHAWEEP, Y.; KAEWKHAO, J. Study on physical, optical and luminescence of Er<sup>3+</sup> in K<sub>2</sub>O-CaO-B<sub>2</sub>O<sub>3</sub> glasses for photonic application. Journal of Metals, Materials and Minerals, Bangkok, Thailand, v. 27, n. 1, 2017. Disponível em: http://jmmm.material.chula.ac.th/index.php/jmmm/article/view/328. Acesso em: 2 dec. 2021.