Virtual-environment.md

@@ -72,7 +72,7 @@ jupyterlab
 requests[security]
 ```
 
-With [version specifier](https://packaging.python.org/en/latest/specifications/version-specifiers/#id5) and environment marker, you can be more precise.
+With [version specifier](https://packaging.python.org/en/latest/specifications/version-specifiers/#id5) and [environment marker](https://peps.python.org/pep-0508/#environment-markers), you can be more precise.
 
 ```txt
 numpy>1.20