diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 36c5c4f..b1a3538 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -10,10 +10,15 @@
 
 ## Naming identifiers
 
-Functions are written with UpperCamelCase and verb is followed by noun.
+Extern functions and variables are written with UpperCamelCase, non-extern functions and variables are written with lowerCamelCase.
+
+Function names are composed of a verb followed by a noun.
 
 ```
-DoThis();
+DoThisExtern();
+doThisNonExtern();
+uint8 ExternVariable;
+uint8 nonExternVariable;
 ```
 
 Whenever a file exposes a group of functions as a consistent API, their function names should be prefixed with the group name, followed by `_`, followed by the individual function names.
@@ -24,12 +29,6 @@ void LedDriver_WriteRegister(uint8_t i2cAddress, uint8_t reg, uint8_t val);
 void LedDriver_SetAllLedsTo(uint8_t val);
 ```
 
-Non-function scoped variables are written with UpperCamelCase.
-
-```
-uint8_t OuterVariable;
-```
-
 Function scoped variables and function parameters are written with lowerCamelCase.
 
 ```