This routine, in Labview 2018, calculates the absolute values of the thermopower for each leg of a given thermocouple among the most popular (K, S, E, etc).
The documentation and references are listed in the routine. For instance, for Chromel leg
Chromel (june 2013) , valid from 300K to 873K
Ahmad et al, j phys 1974
Coefficient values ± one standard deviation
K0 = 0.47481 ± 0.0426
K1 = 0.14805 ± 0.000973
K2 = -0.0003499 ± 6.83e-06
K3 = 3.5873e-07 ± 1.97e-08
K4 = -2.1636e-10 ± 2.48e-11
K5 = 7.13e-14 ± 1.13e-14
Polynomial fit, temp in K, output in microVolts per Kelvin (within +/- 0.5 microV)
When measuring Seebeck coeficients one needs the absolute values of the leg, if the potential difference is measured through a thermocouple leg. Be aware that some producers of thermocouples do not use standard legs, they are only concerned witht the difference between legs.
The file an be downloaded here.