forked from mpusz/mp-units
in accordance with https://www.bipm.org/documents/20126/41483022/SI-Brochure-9.pdf#page=147 see also disccusion thread #292
in accordance with https://www.bipm.org/documents/20126/41483022/SI-Brochure-9.pdf#page=147 see also disccusion thread #292