diff --git a/src/display/api.js b/src/display/api.js
index 3363923b1..f06cb3142 100644
--- a/src/display/api.js
+++ b/src/display/api.js
@@ -114,6 +114,12 @@ function setPDFNetworkStreamFactory(pdfNetworkStreamFactory) {
  * } TypedArray
  */
 
+/**
+ * @typedef {Object} RefProxy
+ * @property {number} num
+ * @property {number} gen
+ */
+
 /**
  * Document initialization / loading parameters object.
  *
@@ -761,12 +767,6 @@ class PDFDocumentProxy {
     return this._transport.getPage(pageNumber);
   }
 
-  /**
-   * @typedef {Object} RefProxy
-   * @property {number} num
-   * @property {number} gen
-   */
-
   /**
    * @param {RefProxy} ref - The page reference.
    * @returns {Promise<number>} A promise that is resolved with the page index,
@@ -1231,8 +1231,7 @@ class PDFPageProxy {
   }
 
   /**
-   * @type {Object} The reference that points to this page. It has `num` and
-   *   `gen` properties.
+   * @type {RefProxy | null} The reference that points to this page.
    */
   get ref() {
     return this._pageInfo.ref;