1. CIPM, 58 Session: Recommendation 1 (1969), p. 30, https://www.bipm.org/en/CIPM/db/1969/1/, acc. Aug. 31, 2020.
2. Comité Consultatif des Unités, 7 session: Recommendation U1 (1980), p. U12, https://www.bipm.org/utils/common/pdf/CC/CCU/CCU7.pdf, acc. Aug. 31, 2020.
3. CIPM, 69 Session: Recommendation 1 (CI-1980) (1980), p. 24, https://www.bipm.org/utils/common/pdf/CIPM-PVOCR/CIPM1980.pdf, acc. Aug. 31, 2020.
4. The International System of Units (SI) (1985), 5th ed., https://www.bipm.org/utils/common/pdf/si_brochure_5.pdf, acc. Aug. 31, 2020.
5. T. J. Quinn, Metrologia, 33, 1, 81–89 (1996), https://doi.org/10.1088/0026-1394/33/1/11.