Merge pull request #51749 from edburns/edburns-MSFT-template-function-nits

Add emphasis on the importance of the apiVersion.

Author: ktoliver

articles/azure-resource-manager/templates/template-functions-resource.md

@@ -438,12 +438,12 @@ Returns an object representing a resource's runtime state.
 | Parameter | Required | Type | Description |
 |:--- |:--- |:--- |:--- |
 | resourceName or resourceIdentifier |Yes |string |Name or unique identifier of a resource. When referencing a resource in the current template, provide only the resource name as a parameter. When referencing a previously deployed resource or when the name of the resource is ambiguous, provide the resource ID. |
-| apiVersion |No |string |API version of the specified resource. Include this parameter when the resource isn't provisioned within same template. Typically, in the format, **yyyy-mm-dd**. For valid API versions for your resource, see [template reference](/azure/templates/). |
+| apiVersion |No |string |API version of the specified resource. **This parameter is required when the resource isn't provisioned within same template.** Typically, in the format, **yyyy-mm-dd**. For valid API versions for your resource, see [template reference](/azure/templates/). |
 | 'Full' |No |string |Value that specifies whether to return the full resource object. If you don't specify `'Full'`, only the properties object of the resource is returned. The full object includes values such as the resource ID and location. |
 
 ### Return value
 
-Every resource type returns different properties for the reference function. The function doesn't return a single, predefined format. Also, the returned value differs based on whether you specified the full object. To see the properties for a resource type, return the object in the outputs section as shown in the example.
+Every resource type returns different properties for the reference function. The function doesn't return a single, predefined format. Also, the returned value differs based on the value of the `'Full'` argument. To see the properties for a resource type, return the object in the outputs section as shown in the example.
 
 ### Remarks
 
@@ -508,7 +508,7 @@ When referencing a resource that is deployed in the same template, provide the n
 "value": "[reference(parameters('storageAccountName'))]"
 ```
 
-When referencing a resource that isn't deployed in the same template, provide the resource ID.
+When referencing a resource that isn't deployed in the same template, provide the resource ID and `apiVersion`.
 
 ```json
 "value": "[reference(resourceId(parameters('storageResourceGroup'), 'Microsoft.Storage/storageAccounts', parameters('storageAccountName')), '2018-07-01')]"