diff --git a/client_http.hpp b/client_http.hpp
index cf62b52..65eb63c 100644
--- a/client_http.hpp
+++ b/client_http.hpp
@@ -17,6 +17,7 @@ namespace SimpleWeb {
         class Response {
             friend class ClientBase<socket_type>;
             
+            //Based on http://www.boost.org/doc/libs/1_60_0/doc/html/unordered/hash_equality.html
             class iequal_to {
             public:
               bool operator()(const std::string &key1, const std::string &key2) const {
diff --git a/server_http.hpp b/server_http.hpp
index 84e9d8b..4a47390 100644
--- a/server_http.hpp
+++ b/server_http.hpp
@@ -61,6 +61,7 @@ namespace SimpleWeb {
         class Request {
             friend class ServerBase<socket_type>;
             
+            //Based on http://www.boost.org/doc/libs/1_60_0/doc/html/unordered/hash_equality.html
             class iequal_to {
             public:
               bool operator()(const std::string &key1, const std::string &key2) const {