diff --git a/content/page/specs.md b/content/page/specs.md
index 19ea833694a47b7efbee19dd43dab9fb0aa0361f..1a2836f5e4f04018d7a6eec42d7d50bc4ffa9969 100644
--- a/content/page/specs.md
+++ b/content/page/specs.md
@@ -29,7 +29,6 @@ The current version: 0.4.0.
 |----|----|----|
 | 1 | exactly one | yes |
 | ? | zero or one | no |
-| * | zero or more | no |
 
 ### Data Types
 
@@ -165,7 +164,7 @@ versions.
 | role | 1 | [string] | the role of a personal entity in relation to the parent object, MUST be `collector` in case of collections |
 | name | 1 | string | the principal name of the person |
 | id | ? | string | internal identifier |
-| idref | * | [Idref Object](#idref-object) | authority files related to the person |
+| idref | ? | \[[Idref Object](#idref-object)\] | authority files related to the person |
 
 #### Metadata Object
 
diff --git a/openapi_3.0.2_specification.yml b/openapi_3.0.2_specification.yml
index c128db6e874cd63c93f3565a7aff7bec061182f1..3ab115c038d95d2f3fa713d2c9c23c717c177c5f 100644
--- a/openapi_3.0.2_specification.yml
+++ b/openapi_3.0.2_specification.yml
@@ -295,17 +295,18 @@ components:
         id:
           type: string
         idref:
-          type: object
-          required:
-          - type
-          - id
-          properties:
-            base:
-              $ref: '#/components/schemas/URL'
-            type:
-              type: string
-            id:
-              type: string
+          type: array
+          items:
+            required:
+            - type
+            - id
+            properties:
+              base:
+                $ref: '#/components/schemas/URL'
+              type:
+                type: string
+              id:
+                type: string
 
     SequenceObject:
       type: object
diff --git a/schema/actor.json b/schema/actor.json
index 8e88d1c31df0ba7d79c8180a5a079cd83e20e044..d17983a09fd22158f2a7021b36ff38c85fe8f613 100644
--- a/schema/actor.json
+++ b/schema/actor.json
@@ -22,7 +22,12 @@
     },
     "idref": {
       "description": "authority files related to the person",
-      "$ref": "idref.json"
+      "type": "array",
+      "items": {
+        "$ref": "idref.json",
+        "minItems": 1,
+        "uniqueItems": true
+      }
     }
   },
   "required": [ "role", "name" ],