--- a/thys3/README.md	Thu Apr 28 15:56:22 2022 +0100
+++ b/thys3/README.md	Sat Apr 30 00:50:08 2022 +0100
@@ -4,6 +4,10 @@
 
 ```isabelle build -c -v -d . Posix```
 
+Generate the paper with
+
+```isabelle build -c -v -d . Paper```
+
 Tested with Isabelle2021-1.