Zmojda, Jacek Mariusz, et al. “Local Field Effect in Antimony-Germanate Glasses Co-Doped With Rare-Earth Ions and Silver Nanoparticles”. Photonics Letters of Poland, vol. 9, no. 4, Dec. 2017, pp. pp. 107-109, doi:10.4302/plp.v9i4.791.