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to the Werthamer-Helfand-Hohenberg (WHH) formula[25] H c 2 (0) = − 0 . 69( dH c 2 /dT ) T c and taking 19 K as Tc, the upper critical fields are estimated to be H ab c $_{2}$=62 T and H c c $_{2}$=31 T. The ratio of H ab c $_{2}$/H c c 2 is about 2 which means the anisotropy is not so large even the upper critical fields are high. 

