A Visual Basic project can reference another Visual Basic project, if the second project exposes a type library. An instance of the MdoProjectRef class represents a Visual Basic project reference in the repository.
| Interface | Description |
| IMdoModelItem | Maintains properties that are common to many different types of MDO Model objects. |
| IMdoReference | Maintains the relationship between two Visual Basic projects, where one project references the other project. |
| IRepositoryItem | Manages repository objects and relationships. |
| IRepositoryObject | Retrieves repository object identifiers. |
| IRepositoryObjectStorage | Creates and loads repository objects. |