1. BIPM, an intergovernmental organization which acts on matters related to measurement science and measurement standards, responsible for the SI base units, https://www.bipm.org/en/measurement-units/si-base-units, 03 December 2022.
2. International Vocabulary of Metrology (VIM), third ed., BIPM JCGM 200:2012, quantity 1.1. 03 December 2022.
3. L. Euler, Elements of Algebra, Chapter I, Article I, #3. Third ed., Longman, Hurst, Rees, Orme and Co., London England, 1822. “Now, we cannot measure or determine any quantity, except by considering some other quantity of the same kind as known, and pointing out their mutual relation.”
4. A. Einstein, B. Podolsky, N. Rosen, Can quantum-mechanical description of physical reality be considered complete?, Physical Review, Vol 47, May 15, 1935. This paper is often referred to as the EPR paper.
5. J. de Boer, On the History of Quantity Calculus and the International System, Metrologia, Vol 31, page 405, 1995.