Zmojda, J., Dorosz, D., Kochanowicz, M., & Dorosz, J. (2010). Spectroscopic properties of Yb3+/Er3+ - doped antimony-phosphate glasses for fiber amplifiers. Photonics Letters of Poland, 2(2), pp. 76–78. https://doi.org/10.4302/photon. lett. pl.v2i2.122