diff --git a/versions/3.0.md b/versions/3.0.md
index 66610d5c4f..728f9c9b83 100644
--- a/versions/3.0.md
+++ b/versions/3.0.md
@@ -411,7 +411,7 @@ Field Name | Type | Description
 
 This object can be extended with [Specification Extensions](#specificationExtensions). 
 
-All the fixed fields declared above are objects that MUST use keys that match the regular expression: `[a-zA-Z0-9.\-_]+`.
+All the fixed fields declared above are objects that MUST use keys that match the regular expression: `^[a-zA-Z0-9\.\-_]+$`.
 
 Field Name Examples: