1. Technical Annexe to MeP of the kelvin (for ITS-90, adopted by the CCT during its Meeting nr 26 of 2012) https://www.bipm.org/utils/en/pdf/MeP_K_Technical_Annex.pdf, now Technical Annex for the International Temperature Scale of 1990 (ITS-90) under https://www.bipm.org/en/committees/cc/cct/publications-cc.html#kelvin-and-temperature-scales and, since May 20, 2019 indicated in: Mise en pratique for the definition of the kelvin in the SI: https://www.bipm.org/utils/en/pdf/si-mep/SI-App2-kelvin.pdf, also Ref. 3 Appendix 2.
2. CGPM, Resolution 1 of the 26th Meeting, 16 November 2018, BIPM, Sèvres. https://www.bipm.org/en/CGPM/db/26.
3. New 9th SI Brochure, BIPM, Sèvres, 2019. https://www.bipm.org/en/publications/si-brochure/.
4. https://www.bipm.org/en/committees/cc/cct/guide-its90.html.
5. NPL-75: A Low Temperature Gas Thermometry Scale from 2.6 K to 27.1 K;Berry;Metrologia,1979