Material Properties: OFHC Copper by National Institute of Standards and Technology

Official data and fitted coefficients: trc.nist.gov/cryogenics/materials/OFHC%20Copper/OFHC_Copper_rev1.htm

The specific-heat correlation covers 4–300 K and gives mass-specific heat capacity in $\mathrm{J}\mathrm{k}{\mathrm{g}}^{-1}{\mathrm{K}}^{-1}$. Its stated fit deviation is 10% below 15 K. The page distinguishes specific heat from its separate thermal conductivity correlation.