https://doi.org/10.1351/goldbook.H02781
An equation of the form: pH=pKalog10([HA][A]) for the calculation of the pH of solutions where the ratio [HA][A] is known.
Source:
PAC, 1994, 66, 1077. (Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)) on page 1120 [Terms] [Paper]