Towards Interoperability: Vertical Integration of Languages with a KBMS. - Wolfgang Benn; Christian Kortenbreer; Xinglin Wu (BTW, 1991)

An approach to support interoperable systems - the meta-level description of type transformation. - Xinglin Wu (1992)

On Interoperability for KBMS Applications - The Horizontal Integration Task. - Wolfgang Benn; Christian Kortenbreer; Gunter Schlageter; Xinglin Wu (ICDE, 1992)