Update README.md

or00101 · web-flow · commit 80ea92e7a2aa · 2020-10-29T17:18:41.000+02:00
diff --git a/README.md b/README.md
@@ -1 +1,3 @@
-# AX.25-UI-Encoder-Decoder
+# AX.25-UI-Encoder-Decoder
+
+AX.25 UI explenation: https://www.tapr.org/pdf/DCC1998-PICet-W2FS.pdf
