diff --git a/spec/factories/call_for_papers.rb b/spec/factories/call_for_papers.rb
index 114defb2..eba5dc9e 100644
--- a/spec/factories/call_for_papers.rb
+++ b/spec/factories/call_for_papers.rb
@@ -1,3 +1,5 @@
+# Read about factories at https://github.com/thoughtbot/factory_girl
+
 FactoryGirl.define do
   factory :call_for_papers do
     start_date Date.today - 1
diff --git a/spec/factories/conferences.rb b/spec/factories/conferences.rb
index 5f18a86c..4479e678 100644
--- a/spec/factories/conferences.rb
+++ b/spec/factories/conferences.rb
@@ -1,3 +1,5 @@
+# Read about factories at https://github.com/thoughtbot/factory_girl
+
 FactoryGirl.define do
   factory :conference do
     title 'The dog and pony show'
diff --git a/spec/factories/users.rb b/spec/factories/users.rb
index 79f9445f..0334d49e 100644
--- a/spec/factories/users.rb
+++ b/spec/factories/users.rb
@@ -1,3 +1,5 @@
+# Read about factories at https://github.com/thoughtbot/factory_girl
+
 FactoryGirl.define do
   factory :user do
     email 'example@example.com'