https://doi.org/10.1351/goldbook.M03709
@B00609@ in the system of quantities upon which SI is based.
Sources:
Green Book, 2nd ed., p. 12 [Terms] [Book]
PAC, 1996, 68, 957. (Glossary of terms in quantities and units in Clinical Chemistry (IUPAC-IFCC Recommendations 1996)) on page 979 [Terms] [Paper]