diff --git a/include/sp/protocol/Message.h b/include/sp/protocol/Message.h
index 4837aea..a83ca82 100644
--- a/include/sp/protocol/Message.h
+++ b/include/sp/protocol/Message.h
@@ -1,5 +1,8 @@
 #pragma once
 
+// Inspired by
+// https://alex-robenko.gitbook.io/comms-protocols-cpp
+
 #include <sp/protocol/MessageInterfaceBuilder.h>
 
 namespace sp {