diff --git a/Makefile b/Makefile
index 63bca95..b975aa8 100644
--- a/Makefile
+++ b/Makefile
@@ -4,7 +4,7 @@
 # You can set these variables from the command line.
 SPHINXOPTS    =
 SPHINXBUILD   = sphinx-build
-PAPER         =
+PAPER         = a4
 BUILDDIR      = build
 
 # User-friendly check for sphinx-build