Prajzler, V., Z. Burian, I. Hüttel, J. Špirková, J. Hamáček, J. Oswald, J. Zavadil, and V. Peřina. 2006. “Properties of Erbium and Ytterbium Doped Gallium Nitride Layers Fabricated by Magnetron Sputtering”. Acta Polytechnica 46 (6). https://doi.org/10.14311/900.