diff --git a/etk/math/Vector3D.cpp b/etk/math/Vector3D.cpp
index 190a55b..40ebb53 100644
--- a/etk/math/Vector3D.cpp
+++ b/etk/math/Vector3D.cpp
@@ -20,7 +20,7 @@ std::ostream& etk::operator <<(std::ostream& _os, const ivec3& _obj) {
 	return _os;
 }
 
-std::ostream& etk::operator <<(std::ostream& _os, const vec3& _obj) {
+std::ostream& operator <<(std::ostream& _os, const vec3& _obj) {
 	_os << "(";
 	_os << _obj.x();
 	_os << ",";
diff --git a/etk/math/Vector3D.h b/etk/math/Vector3D.h
index 5f153c6..519fb36 100644
--- a/etk/math/Vector3D.h
+++ b/etk/math/Vector3D.h
@@ -443,14 +443,13 @@ namespace etk {
 	 */
 	std::ostream& operator <<(std::ostream& _os, const etk::Vector3D<int32_t>& _obj);
 	//! @previous
-	std::ostream& operator <<(std::ostream& _os, const btVector3& _obj);
-	//! @previous
 	std::ostream& operator <<(std::ostream& _os, const etk::Vector3D<uint32_t>& _obj);
 	//! @previous
 	std::ostream& operator <<(std::ostream& _os, const etk::Vector3D<bool>& _obj);
-	
 };
 
+std::ostream& operator <<(std::ostream& _os, const btVector3& _obj);
+
 // To siplify the writing of the code ==> this permit to have the same name with the glsl language...
 typedef btVector3                 vec3;
 typedef etk::Vector3D<float>     ovec3;  // specific for OpenGL ... ==> never change this ...