## Wikipedia - Atomo mass number, $$A$$

https://doi.org/10.1351/goldbook.M03726
Total number of heavy particles (protons and neutrons jointly called nucleons) in the atomic @N04256@. Also called @N04248@. Symbol $$m$$ in @M03746@.
Sources:
Green Book, 2nd ed., p. 20 [Terms] [Book]
PAC, 1991, 63, 1541. (Recommendations for nomenclature and symbolism for mass spectroscopy (including an appendix of terms used in vacuum technology). (Recommendations 1991)) on page 1545 [Terms] [Paper]
PAC, 1996, 68, 957. (Glossary of terms in quantities and units in Clinical Chemistry (IUPAC-IFCC Recommendations 1996)) on page 980 [Terms] [Paper]
Red Book, 3rd ed., p. 35 [Terms] [Book]