diff --git a/src/frontends/qt4/QCitationDialog.C b/src/frontends/qt4/QCitationDialog.C
index 18d0ebc1e9..b63cada9a2 100644
--- a/src/frontends/qt4/QCitationDialog.C
+++ b/src/frontends/qt4/QCitationDialog.C
@@ -23,6 +23,7 @@
 #include "debug.h"
 #include "gettext.h"
 
+#include <algorithm>
 #include <vector>
 #include <string>