  Low-temperature-resistivity plateau observed in $\rm SmB_6$ single
crystal,which is due to surface, not bulk, conduction has been confirmed from
electrical transport measurements. Recently, the correlation between bulk
thermodynamic measurements and the low-temperature-resistance plateau in $\rm
SmB_6$ have been investigated and a change in Sm valence at the surface has
been obtained from x-ray absorption spectroscopy and x-ray magnetic circular
dichroism. Here we show that the statement of the report are not supported by
the results from x-ray absorption spectroscopy and x-ray magnetic circular
dichroism.
