diff --git a/toppers/csv.hpp b/toppers/csv.hpp
index 7b25513..42a4aef 100644
--- a/toppers/csv.hpp
+++ b/toppers/csv.hpp
@@ -49,6 +49,7 @@
 #include <vector>
 #include <algorithm>
 #include <boost/utility.hpp>
+#include <boost/next_prior.hpp>
 #include "toppers/misc.hpp"
 
 namespace toppers