diff --git a/docs/howto/outputting-pdf.txt b/docs/howto/outputting-pdf.txt
index d15f94f7f4..0ce3cbb724 100644
--- a/docs/howto/outputting-pdf.txt
+++ b/docs/howto/outputting-pdf.txt
@@ -154,8 +154,8 @@ Further resources
   using ``system`` or ``popen`` and retrieve the output in Python.
 
 .. _PDFlib: http://www.pdflib.org/
-.. _`Pisa XHTML2PDF`: http://www.xhtml2pdf.com/
-.. _HTMLdoc: http://www.htmldoc.org/
+.. _`Pisa XHTML2PDF`: https://github.com/xhtml2pdf/xhtml2pdf
+.. _HTMLdoc: https://www.msweet.org/projects.php?Z1
 
 Other formats
 =============