diff --git a/certificate.yml b/certificate.yml
index 6b1c2a0..73018cc 100644
--- a/certificate.yml
+++ b/certificate.yml
@@ -1 +1,3 @@
-# Correctly setup Let's Encrypt certificate renewal
\ No newline at end of file
+# Correctly setup Let's Encrypt certificate renewal
+# https://docs.ansible.com/ansible/latest/modules/acme_certificate_module.html
+# https://github.com/geerlingguy/ansible-role-certbot
\ No newline at end of file