How can I add "AxTAPIExLib" reference in my C# project?

In the mainmenu,

1. "View" -> "Toolbar"
2. Right Click in the "Toolbar" window, and in the pop menu click "Customize Toolbox"
3. "Customize Toolbox" window will be displayed, select "TAPIEx class" in the "COM Components" session, and Click "OK"
4. After that you will find "TAPIEx_b" control in the "Toolbox" , after you drop it into the form, "AxTAPIExLib" will be added.