src/JsonApiResource/JsonApiDocumentTopLevel.php                 | 5 +++--
 src/Normalizer/Value/JsonApiDocumentTopLevelNormalizerValue.php | 2 ++
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/JsonApiResource/JsonApiDocumentTopLevel.php b/src/JsonApiResource/JsonApiDocumentTopLevel.php
index dc98c7e..1dd47ac 100644
--- a/src/JsonApiResource/JsonApiDocumentTopLevel.php
+++ b/src/JsonApiResource/JsonApiDocumentTopLevel.php
@@ -36,7 +36,8 @@ class JsonApiDocumentTopLevel {
    *   The data to normalize. It can be either a straight up entity or a
    *   collection of entities.
    * @param \Drupal\Core\Url[]|string[] $links
-   *   The URLs to which to link.
+   *   The URLs to which the top-level document should link. Keys are link
+   *   relation types. Values are URLs.
    */
   public function __construct($data, array $links) {
     assert(empty(array_diff(array_keys($links), ['self', 'first', 'next', 'prev', 'last', 'related'])));
@@ -62,7 +63,7 @@ class JsonApiDocumentTopLevel {
    * Gets the links.
    *
    * @return \Drupal\Core\Url[] $links
-   *   The document-level links.
+   *   The top-level links.
    */
   public function getLinks() {
     return $this->links;
diff --git a/src/Normalizer/Value/JsonApiDocumentTopLevelNormalizerValue.php b/src/Normalizer/Value/JsonApiDocumentTopLevelNormalizerValue.php
index 5bbaaad..6d8465b 100644
--- a/src/Normalizer/Value/JsonApiDocumentTopLevelNormalizerValue.php
+++ b/src/Normalizer/Value/JsonApiDocumentTopLevelNormalizerValue.php
@@ -26,6 +26,8 @@ class JsonApiDocumentTopLevelNormalizerValue implements ValueExtractorInterface,
   protected $values;
 
   /**
+   * The links. Keys are link relation types.
+   *
    * @var array|\Drupal\Core\Url[]|string[]
    */
   protected $links;