SI UNITS – ampere (A). National Physical Laboratory (Brit Mérésügyi Laboratórium). (Hozzáférés: 2020. november 6.) „The ampere is defined by taking the fixed numerical value of the elementary charge e to be 1.602 176 634 × 10−19 when expressed in the unit C, which is equal to A s, where the second is defined in terms of ∆ν.”