https://doi.org/10.1351/goldbook.K03374

The kelvin, symbol \(\text{K}\), is the SI unit of thermodynamic temperature. It is defined by taking the fixed numerical value of the Boltzmann constant k to be 1.380 649 x 10E-23 when expressed in the unit J K-1, which is equal to kg m2 s-2 K-1, where the kilogram, metre and second are defined in terms of *h*, *c* and Δ*ν*_{Cs}.*Source: *

BIPM, The International System of Units, SI Brochure, 9^{th} ed. (2019) (http://www.bipm.org/en/publications/si-brochure/)

BIPM, The International System of Units, SI Brochure, 9