diff --git a/src/main/java/ru/dmitriymx/vkapi/VkApi.java b/src/main/java/ru/dmitriymx/vkapi/VkApi.java
index 09d5bf4..86244b9 100644
--- a/src/main/java/ru/dmitriymx/vkapi/VkApi.java
+++ b/src/main/java/ru/dmitriymx/vkapi/VkApi.java
@@ -115,6 +115,7 @@ public class VkApi implements Runnable {
         }
     }
 
+    // https://vk.com/dev/using_longpoll
     public JsonObject longExecApi(String server, String key, long ts, long wait) throws IOException {
         String url = String.format("https://%s?act=a_check&key=%s&ts=%d&wait=%d&mode=2&version=1",
                                    server, key, ts, wait