Zmojda, Jacek, et al. ‚ÄúSpectroscopic Properties of Yb3+ Er3+ - Doped Antimony-Phosphate Glasses for Fiber Amplifiers‚ÄĚ. Photonics Letters of Poland, vol. 2, no. 2, June 2010, pp. pp. 76-78, doi:10.4302/photon. lett. pl.v2i2.122.