Bobrov, N.; Chernobay, V.; Naidyuk, Y.; Tyutrina, L.; Yanson, I.; Naugle, D.; Rathnayaka, K. Observation of Anisotropic Effect of Antiferromagnetic Ordering on the Superconducting Gap in ErNi₂B₂C. Fiz. Nizk. Temp. 2010, 36, 1228-1243.