diff --git a/app/lib/renderer/lesson.rb b/app/lib/renderer/lesson.rb
index c72fea6..07bb394 100644
--- a/app/lib/renderer/lesson.rb
+++ b/app/lib/renderer/lesson.rb
@@ -10,7 +10,7 @@ class Lesson
     attr_accessor :disable_transcripts
 
     def render
-      logger.info "Beginning lesson render: #{object.title}"
+      logger.info "Beginning lesson render: #{object.ref} #{object.title}"
       attach_images
       render_markdown
       object.segments.each do |segment|
diff --git a/app/models/lesson.rb b/app/models/lesson.rb
index 3c39c50..323838c 100644
--- a/app/models/lesson.rb
+++ b/app/models/lesson.rb
@@ -11,7 +11,7 @@ class Lesson
 
   attr_markdown :description, source: :description_md, file: false
   attr_markdown :learning_objectives, source: :learning_objectives_md, file: false
-  validates :title, :ordinal, presence: true
+  validates :title, :ordinal, :ref, presence: true
 
   def initialize(attributes = {})
     super