Hopefully last updates

Author: webron

versions/3.0.md

@@ -2214,7 +2214,7 @@ definitions:
 
 A simple object to allow referencing other definitions in the specification, internally and externally.
 
-The Reference Object is defined by [JSON Reference](https://tools.ietf.org/html/draft-pbryan-zyp-json-ref-03) and follows the same structure, behavior and rules.
+The Reference Object is defined by [JSON Reference](https://tools.ietf.org/html/draft-pbryan-zyp-json-ref-03) and follows the same structure, behavior and rules. 
 
 For this specification, reference resolution is done as defined by the JSON Reference specification and not by the JSON Schema specification.
 
@@ -2223,6 +2223,8 @@ Field Name | Type | Description
 ---|:---:|---
 <a name="referenceRef"></a>$ref | `string` | **Required.** The reference string. 
 
+This object cannot be extended with additional properties and any properties added SHALL be ignored.
+
 ##### Reference Object Example
 
 ```json
@@ -2298,7 +2300,7 @@ The following properties are taken from the JSON Schema definition but their def
 - format - See [Data Type Formats](#dataTypeFormat) for further details. While relying on JSON Schema's defined formats, the OAS offers a few additional predefined formats.
 - default - The default value represents what would be assumed by the consumer of the input as the value of the schema if one is not provided. Unlike JSON Schema, the value MUST conform to the defined type for the Schema Object defined at the same level. For example, of `type` is `string`, then `default` can be `"foo"`` but cannot be `1`.
 
-Alternatively, any time a Scheme Object can be used, a [Reference Object](#referenceObject) can be used in place. This allows referencing definitions in place of defining them inline. Effectively, it is the `$ref` property in JSON Schema but follows the same guidelines and restrictions as the Reference Object. For example, additional properties alongside a `$ref` SHALL be ignored.
+Alternatively, any time a Scheme Object can be used, a [Reference Object](#referenceObject) can be used in its place. This allows referencing definitions in place of defining them inline.
 
 Additional properties defined by the JSON Schema specification that are not mentioned here are strictly unsupported.