diff --git a/reference/orders.sf.yml b/reference/orders.sf.yml
index 4ac444d39..174d2cfb6 100644
--- a/reference/orders.sf.yml
+++ b/reference/orders.sf.yml
@@ -49,6 +49,14 @@ paths:
           description: Sub-resources to include in an Order, in a comma-separated list. The ID and the specified fields will be returned.
           schema:
             type: string
+            enum:
+              - lineItems
+              - billingAddress
+              - coupons
+              - currency
+              - taxes
+              - payments
+              - consignments
       responses:
         '200':
           description: ''