diff --git a/doc/Doxyfile.in b/doc/Doxyfile.in
index 8f61a060b37b0e62189160d0a8c61e713cfd3b8f..690ca1afeca5b3926c168d876e19d32dff5c9917 100644
--- a/doc/Doxyfile.in
+++ b/doc/Doxyfile.in
@@ -759,7 +759,7 @@ WARN_LOGFILE           =
 # spaces.
 # Note: If this tag is empty the current directory is searched.
 
-INPUT                  = @top_srcdir@ @top_srcdir@/src @top_srcdir@/src/hydro/Minimal @top_srcdir@/src/gravity/Default
+INPUT                  = @top_srcdir@ @top_srcdir@/src @top_srcdir@/src/hydro/Minimal @top_srcdir@/src/gravity/Default @top_srcdir@/riemann
 
 # This tag can be used to specify the character encoding of the source files
 # that doxygen parses. Internally doxygen uses the UTF-8 encoding. Doxygen uses