Sutherland, M.; Doiron-Leyraud, N.; Taillefer, L.; Weller, T.; Ellerby, M.; Saxema, S.S.; (2007) Bulk evidence for single-gap s-wave superconductivity in the intercalated graphite superconductor C_{6}Yb. Physical Review Letters , 98 (6) 067003. 10.1103/PhysRevLett.98.067003.