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molar volume of ideal gas (273.15 K, 101.325 kPa) The NIST Reference on Constants, Units, and Uncertainty. US National Institute of Standards and Technology. 2019-05-20. 2018 CODATA recommended values
molar mass of carbon-12 The NIST Reference on Constants, Units, and Uncertainty. US National Institute of Standards and Technology. 2019-05-20. 2018 CODATA recommended values