diff --git a/docs/source/FlexBuffers.md b/docs/source/FlexBuffers.md
index 67c9b275b..5d592fea9 100644
--- a/docs/source/FlexBuffers.md
+++ b/docs/source/FlexBuffers.md
@@ -125,7 +125,7 @@ map["unknown"].IsNull();  // true
 # Binary encoding
 
 A description of how FlexBuffers are encoded is in the
-[internals](@ref flatbuffers_internals) document.
+[internals](Internals.md#flexbuffers) document.
 
 
 # Efficiency tips
diff --git a/include/flatbuffers/flexbuffers.h b/include/flatbuffers/flexbuffers.h
index 6c3012c3e..a5d24fd4f 100644
--- a/include/flatbuffers/flexbuffers.h
+++ b/include/flatbuffers/flexbuffers.h
@@ -17,6 +17,7 @@
 #ifndef FLATBUFFERS_FLEXBUFFERS_H_
 #define FLATBUFFERS_FLEXBUFFERS_H_
 
+#include <map>
 // We use the basic binary writing functions from the regular FlatBuffers.
 #include "flatbuffers/flatbuffers.h"
 #include "flatbuffers/util.h"