diff --git a/app/src/main/java/org/tasks/caldav/CaldavConverter.java b/app/src/main/java/org/tasks/caldav/CaldavConverter.java
index 3a4eee4e2..65e6ba546 100644
--- a/app/src/main/java/org/tasks/caldav/CaldavConverter.java
+++ b/app/src/main/java/org/tasks/caldav/CaldavConverter.java
@@ -82,6 +82,7 @@ public class CaldavConverter {
   }
 
   private static @Priority int fromRemote(int remotePriority) {
+    // https://tools.ietf.org/html/rfc5545#section-3.8.1.9
     if (remotePriority == 0) {
       return Priority.NONE;
     }