diff --git a/wiki/doc/RealQuantity.md b/wiki/doc/RealQuantity.md
index 04dc16c8b19a432724d7948fc4b67af961248872..283dd885196b737c9b6e01571c82186fed79313b 100644
--- a/wiki/doc/RealQuantity.md
+++ b/wiki/doc/RealQuantity.md
@@ -15,6 +15,9 @@
 <img alt="D-SI-Image-1.7" width="600" style="border-width:10" src="wiki/doc/D-SI-1.7.PNG" /></a>
 ---
 <img alt="D-SI-Image-1.8" width="600" style="border-width:10" src="wiki/doc/D-SI-1.8.PNG" /></a>
+
+*Remark: It is in the responsibility of the creator of data to provide correct and consitent values for the expanded uncertianty, the coverage factor and the coverage probability. In case of inconsisten data, the value for the coverage factor should be seen as the "point of truth" in the data.*
+
 <img alt="D-SI-Image-1.9" width="600" style="border-width:10" src="wiki/doc/D-SI-1.9.PNG" /></a>
 ---
 <img alt="D-SI-Image-1.10" width="600" style="border-width:10" src="wiki/doc/D-SI-1.10.PNG" /></a>
diff --git a/wiki/doc/UnitSystem.md b/wiki/doc/UnitSystem.md
index bda0845747e094440e25903320c146227aebcbba..725ce90bf04da90143de05ba53b07e4cf4abfc0e 100644
--- a/wiki/doc/UnitSystem.md
+++ b/wiki/doc/UnitSystem.md
@@ -111,6 +111,12 @@ Description how to build units witht the D-SI format is [here](StructureSIUnits.
 |\zebi|gold|zebi |Zi|1180591620717411303424|[1, p. 143]|
 |\yobi|gold|yobi |Yi|1208925819614629174706176|[1, p. 143]|"
 
+## Operators for combining units
+|D-SI Identifyer|Description|Examples|D-SI Medal |
+|-:|-:|-:|-:|
+| |Multiplication: simply append one unit to another |\metre\metre|PLATINUM|
+|\tothe{n} | Exponent: following a unit where n is an integer or (+-)0.5 |\metre\tothe{2}, \volt\tothe{-0.5}|PLATINUM|
+|\per |Division: All units on the left side of the operator devided by all units on its right side |\metre\per\metre|SILVER|
 
 ### References