diff --git a/doc/users/style_sheets.rst b/doc/users/style_sheets.rst
index 4038496ecbec..ed303b9ccafb 100644
--- a/doc/users/style_sheets.rst
+++ b/doc/users/style_sheets.rst
@@ -84,5 +84,5 @@ changes, you can write something like the following::
 
 
 .. _matplotlibrc: http://matplotlib.org/users/customizing.html
-.. _ggplot: http://had.co.nz/ggplot2/
-.. _R: http://www.r-project.org/
+.. _ggplot: http://ggplot2.org/
+.. _R: https://www.r-project.org/