diff --git a/letsencrypt.sh b/letsencrypt.sh
index 18a2619..cf4d0ca 100755
--- a/letsencrypt.sh
+++ b/letsencrypt.sh
@@ -1,4 +1,8 @@
 #!/usr/bin/env bash
+
+# letsencrypt.sh by lukas2511
+# Source: https://github.com/lukas2511/letsencrypt.sh
+
 set -e
 set -u
 set -o pipefail