Project References Projects can refer to other projects, and you can add project references explicitly or automatically. Allowing projects to refer to other projects means you can do the following: • Invoke a sub-process from another project (see Reusable Sub-processes). • Use a process interface from another project (see Process Interface). • Create a data field or formal parameter of the type external reference (see Data Fields and Parameters). • Select a WSDL from a different project.