diff --git a/src/libvterm/doc/URLs b/src/libvterm/doc/URLs
index 3a6512f..8380f5c 100644
--- a/src/libvterm/doc/URLs
+++ b/src/libvterm/doc/URLs
@@ -9,3 +9,6 @@
 
 Digital VT220 Programmer Reference Manual
   http://vt100.net/docs/vt220-rm/
+
+Summary of ANSI standards for ASCII terminals
+  http://www.inwap.com/pdp10/ansicode.txt