Kosevich, A., Feodosyev, S., Gospodarev, I., Grishaev, V., Kotlyar, O., Kruglov, V., Manzhelii, E., & Syrkin, E. (2007). Evolution of discrete local levels into an impurity band in solidified inert gas solution: Classical Cryocrystals. ФІЗИКА НИЗЬКИХ ТЕМПЕРАТУР, 33(6-7), 735–740. https://doi.org/10.1063/1.2746251