diff --git a/src/server.ts b/src/server.ts
index bd8c6b4..9534cbb 100644
--- a/src/server.ts
+++ b/src/server.ts
@@ -1,3 +1,9 @@
+/**
+ * Resources:
+ * https://deepinder.me/creating-a-real-time-chat-app-with-vue-socket-io-and-nodejs-2
+ * https://socket.io/docs/v4/server-api/
+ */
+
 import express from 'express';
 import { Server } from 'socket.io';
 import http from 'http';