diff --git a/OdbDesignServer/Controllers/HelloWorldController.cpp b/OdbDesignServer/Controllers/HelloWorldController.cpp
index a873ee5b..d3866e09 100644
--- a/OdbDesignServer/Controllers/HelloWorldController.cpp
+++ b/OdbDesignServer/Controllers/HelloWorldController.cpp
@@ -1,4 +1,5 @@
 #include "HelloWorldController.h"
+#include "../OdbDesignServerApp.h"
 
 
 namespace Odb::App::Server
diff --git a/OdbDesignServer/Controllers/HelloWorldController.h b/OdbDesignServer/Controllers/HelloWorldController.h
index 41624485..27303929 100644
--- a/OdbDesignServer/Controllers/HelloWorldController.h
+++ b/OdbDesignServer/Controllers/HelloWorldController.h
@@ -5,6 +5,9 @@
 
 namespace Odb::App::Server
 {
+	// forward declaration
+	class OdbDesignServerApp;
+
 	class HelloWorldController : public RouteController
 	{
 	public:
diff --git a/OdbDesignServer/Controllers/StepsEdaDataController.cpp b/OdbDesignServer/Controllers/StepsEdaDataController.cpp
index 47a39777..e3ad37aa 100644
--- a/OdbDesignServer/Controllers/StepsEdaDataController.cpp
+++ b/OdbDesignServer/Controllers/StepsEdaDataController.cpp
@@ -3,6 +3,7 @@
 #include "EdaDataFile.h"
 #include "JsonCrowReturnable.h"
 #include <sstream>
+#include "../OdbDesignServerApp.h"
 
 using namespace Odb::Lib;
 using namespace FileModel::Design;
diff --git a/OdbDesignServer/Controllers/StepsEdaDataController.h b/OdbDesignServer/Controllers/StepsEdaDataController.h
index 1dafb0c9..8ccfbf55 100644
--- a/OdbDesignServer/Controllers/StepsEdaDataController.h
+++ b/OdbDesignServer/Controllers/StepsEdaDataController.h
@@ -6,6 +6,9 @@
 
 namespace Odb::App::Server
 {
+	// forward declaration
+	class OdbDesignServerApp;
+
 	class StepsEdaDataController : public RouteController
 	{
 	public: