https://doi.org/10.1351/goldbook.A00300

The ampere, symbol \(\text{A}\), is the SI unit of electric current. It is defined by taking the fixed numerical value of the elementary charge e to be 1.602 176 634 x 10E-19 when expressed in the unit C, which is equal to A s, where the second is defined in terms of Δ*ν*_{Cs}.*Source: *

BIPM, The International System of Units, SI Brochure, 9^{th} ed. (2019) (http://www.bipm.org/en/publications/si-brochure/)

BIPM, The International System of Units, SI Brochure, 9