Gurevich, A., Terekhov, A., Kondrashev, D., Dolbin, A., Cassidy, D., Gadd, G., Moricca, S., & Sundqvist, B. (2006). Low-temperature heat capacity of fullerite C₆₀ doped with nitrogen. ФІЗИКА НИЗЬКИХ ТЕМПЕРАТУР, 32(10), 1275–1277. https://doi.org/10.1063/1.2364490