Update UnitSystem.md

wiki/doc/UnitSystem.md

@@ -4,18 +4,19 @@ Description how to build units witht the D-SI format is [here](StructureSIUnits.
 |D-SI Identifyer|D-SI Medal|SI name|SI symbol |SI Reference| 
 |-:|-:|-:|-:|-:| 
 |\metre|platinum|meter|m|[1, Table 2]| 
-|\kilogram<sup>a</sup>|platinum|kilogram|kg|[1, Table 2]| 
+|\kilogram<sup>(a</sup>|platinum|kilogram|kg|[1, Table 2]| 
 |\second|platinum|second|s|[1, Table 2]| 
 |\ampere|platinum|ampere|A|[1, Table 2]| 
 |\kelvin|platinum|kelvin|K|[1, Table 2]| 
 |\mole|platinum|mole|mol|[1, Table 2]| 
 |\candela|platinum|candela|cd|[1, Table 2]|"
 
+<sub>(a: It is not allowed to use unit kilogram with a prefix. </sub>
 
 ## D-SI additional platinum units of measurement 
 |D-SI Identifyer|D-SI Medal|SI name|SI symbol |SI Reference| 
 |-:|-:|-:|-:|-:| 
-|\one|platinum|one|1|[1, Sec. 2.2.1]| 
+|\one<sup>(b</sup>|platinum|one|1|[1, Sec. 2.2.1]| 
 |\day|platinum|day|d|[1, Table 8]| 
 |\hour|platinum|hour|h|[1, Table 8]| 
 |\minute|platinum|minute|min|[1, Table 8]| 
@@ -23,6 +24,7 @@ Description how to build units witht the D-SI format is [here](StructureSIUnits.
 |\arcminute|platinum|arcminute|‘|[1, Table 8]| 
 |\arcsecond|platinum|arcsecond|“|[1, Table 8]|"
 
+<sub>(a: It is not allowed to use unit kilogram with a prefix. </sub>
 
 ## SI derived units of measurement 
 |D-SI Identifyer|D-SI Medal|SI name|SI symbol |SI base unit expression|D-SI base unit expression|SI Reference|