diff --git a/cap07.Rmd b/cap07.Rmd
index 33b07363f8be4fa4ba19353f9b845d1f0017f293..8b1c50154bc42d2cc41bcd04ce04bc6b398b88e0 100644
--- a/cap07.Rmd
+++ b/cap07.Rmd
@@ -16,3 +16,4 @@ source("config.R")
 rty <- "md"
 ```
 
+  * <http://kbroman.org/pkg_primer/pages/tests.html>