Yu. G. Naidyuk, A. V. Moskalenko, I. K. Yanson, and C. Geibel, Point contact studies of the superconducting gap of CeRu₂, Low Temp. Phys. 24, (1998) [Fiz. Nizk. Temp. 24, 495-497, (1998)] DOI: https://doi.org/10.1063/1.593604.