diff --git a/src/JsonApiResource/LinkCollection.php b/src/JsonApiResource/LinkCollection.php
index bc5fb24..25288fd 100644
--- a/src/JsonApiResource/LinkCollection.php
+++ b/src/JsonApiResource/LinkCollection.php
@@ -120,7 +120,7 @@ final class LinkCollection implements \IteratorAggregate {
   /**
    * Gets the LinkCollection's context object.
    *
-   * @return \Drupal\jsonapi\JsonApiResource\JsonApiDocumentTopLevel
+   * @return \Drupal\jsonapi\JsonApiResource\JsonApiDocumentTopLevel|\Drupal\jsonapi\JsonApiResource\ResourceObject
    *   The LinkCollection's context.
    */
   public function getContext() {
@@ -166,11 +166,15 @@ final class LinkCollection implements \IteratorAggregate {
   public static function merge(LinkCollection $a, LinkCollection $b) {
     assert($a->getContext() === $b->getContext());
     $merged = new LinkCollection([], $a->getContext());
-    foreach ($a as $key => $link) {
-      $merged = $merged->withLink($key, $link);
+    foreach ($a as $key => $links) {
+      $merged = array_reduce($links, function (self $merged, Link $link) use ($key) {
+        return $merged->withLink($key, $link);
+      }, $merged);
     }
-    foreach ($b as $key => $link) {
-      $merged = $merged->withLink($key, $link);
+    foreach ($b as $key => $links) {
+      $merged = array_reduce($links, function (self $merged, Link $link) use ($key) {
+        return $merged->withLink($key, $link);
+      }, $merged);
     }
     return $merged;
   }