This text recommends the use of the international system of units (SI), together with the symbols for their representation. It also recommends that other units and symbols in the field of telecommunication should follow similar rules.
ITU-R V.430-4-2015 Referenced Document
ITU-R V.430-4 Use of the international system of units (SI)
ITU-R V.431-8 Nomenclature of the frequency and wavelengh bands used in telecommunications