Giant Sommerfeld coefficient in the heavy-fermion YbBiPt
  It has been derived that the Sommerfeld coefficient $\gamma $ as large as 25 J/K$^2$mol can be theoretically accounted for provided the charge f-electron fluctuations are substantially suppressed. This result enables the understanding of the heavy-fermion YbBiPt ($\gamma $ =8 J/K$^2$mol) as the spin fluctuator and should stimulate the experimental specific-heat research at low temperatures. 
Z.Ropka