Ragiń, T., A. Baranowska, M. Sołtys, A. Górny, J. Zmojda, M. Kochanowicz, P. Mikulski, R. Jadach, and D. Dorosz. “Up-Conversion Luminescence in Low Phonon Heavy Metal Oxide Glass Co-Doped With Er3+ Ho3+”. Photonics Letters of Poland 10, no. 1 (March 31, 2018): 2–4. Accessed April 25, 2024. https://www.photonics.pl/PLP/index.php/letters/article/view/10-2.