Sources:
PAC, 1991, 63, 1227. 'Manual on catalyst characterization (Recommendations 1991)' on page 1230 (https://doi.org/10.1351/pac199163091227)
PAC, 1996, 68, 957. 'Glossary of terms in quantities and units in Clinical Chemistry (IUPAC-IFCC Recommendations 1996)' on page 975 (https://doi.org/10.1351/pac199668040957)