src/Normalizer/Relationship.php   | 4 +++-
 src/Resource/EntityCollection.php | 2 ++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/Normalizer/Relationship.php b/src/Normalizer/Relationship.php
index 319357d..c1cb5ac 100644
--- a/src/Normalizer/Relationship.php
+++ b/src/Normalizer/Relationship.php
@@ -12,7 +12,9 @@ use Drupal\jsonapi\Resource\EntityCollectionInterface;
 /**
  * Class Relationship.
  *
- * Use this class to create a relationship in your normalizer without having an entity reference field.
+ * Use this class to create a relationship in your normalizer without having an
+ * entity reference field: allows for "virtual" relationships that are not
+ * backed by a stored entity reference.
  *
  * @package Drupal\jsonapi
  */
diff --git a/src/Resource/EntityCollection.php b/src/Resource/EntityCollection.php
index 297d56b..a1f6b3e 100644
--- a/src/Resource/EntityCollection.php
+++ b/src/Resource/EntityCollection.php
@@ -5,6 +5,8 @@ namespace Drupal\jsonapi\Resource;
 /**
  * Class EntityCollection.
  *
+ * Wrapper to normalize collections with multiple entities.
+ *
  * @package Drupal\jsonapi
  */
 class EntityCollection implements EntityCollectionInterface {