diff --git a/fi/include/frequent_items_sketch_impl.hpp b/fi/include/frequent_items_sketch_impl.hpp
index e3d4cb0..91a0152 100644
--- a/fi/include/frequent_items_sketch_impl.hpp
+++ b/fi/include/frequent_items_sketch_impl.hpp
@@ -20,9 +20,9 @@
 #ifndef FREQUENT_ITEMS_SKETCH_IMPL_HPP_
 #define FREQUENT_ITEMS_SKETCH_IMPL_HPP_
 
-#include <streambuf>
 #include <cstring>
 #include <limits>
+#include <sstream>
 
 #include "memory_operations.hpp"
 
diff --git a/kll/include/kll_sketch_impl.hpp b/kll/include/kll_sketch_impl.hpp
index e51c311..15d6ae2 100644
--- a/kll/include/kll_sketch_impl.hpp
+++ b/kll/include/kll_sketch_impl.hpp
@@ -22,6 +22,7 @@
 
 #include <iostream>
 #include <iomanip>
+#include <sstream>
 
 #include "memory_operations.hpp"
 #include "kll_helper.hpp"