A. N. Aleksandrovskii, V. G. Manzhelii, V. B. Esel, and B. G. Udovidchenko, New impurity effect in thermal expansion of ¹⁴N₂-Ar solid solutions, Low Temp. Phys. 22, (1996) [Fiz. Nizk. Temp. 22, 345-347, (1996)].