\newcommand{\etalchar}[1]{$^{#1}$}
\begin{thebibliography}{JMW{\etalchar{+}}90}

\bibitem[BJM{\etalchar{+}}89]{BJMSV89}
A.~Borgida, M.~Jarke, J.~Mylopoulos, J.W. Schmidt, and Y.~Vassiliou.
\newblock The Software Development Environment as a Knowledge Base Management
  System.
\newblock In J.W. Schmidt and C.~Thanos, editors, {\em Foundations of Knowledge
  Base Management}, Topics in Information Systems. Springer-Verlag, 1989.

\bibitem[BJS86]{BJS86}
S.~B{\"o}ttcher, M.~Jarke, and J.W. Schmidt.
\newblock Adaptive Predicate Managers in Database Systems.
\newblock In {\em Proc. of the 12th International Conference on VLDB}, Kyoto,
  1986.

\bibitem[B{\"o}t90]{Bott90}
S.~B{\"o}ttcher.
\newblock Improving the Concurrency of Integrity Checks and Write Operations.
\newblock In {\em Proc. ICDT 90}, Paris, December 1990.

\bibitem[Car88]{Card88b}
L.~Cardelli.
\newblock Types for Data-Oriented Languages.
\newblock In {\em Advances in Database Technology, EDBT '88}, volume 303 of
  {\em Lecture Notes in Computer Science}, pages 1--15. Springer-Verlag, 1988.

\bibitem[EEK{\etalchar{+}}85]{EEKM85}
H.~Eckhardt, J.~Edelmann, J.~Koch, M.~Mall, and J.W. Schmidt.
\newblock Draft Report on the Database Programming Language {DBPL}.
\newblock DBPL-Memo 091-85, Fachbereich Informatik, Johann Wolfgang
  Goethe-Universit\"at, Frankfurt, West Germany, 1985.

\bibitem[ERMS91]{ERMS91}
J.~Eder, A.~Rudloff, F.~Matthes, and J.W. Schmidt.
\newblock Data Construction with Recursive Set Expressions in DBPL.
\newblock In {\em Proceedings of the Kiev East/West Workshop on Next Generation
  Database Technology}, volume 504 of {\em Lecture Notes in Computer Science},
  April 1991.

\bibitem[JGL{\etalchar{+}}88]{JGLR88}
W.~Johannsen, L.~Ge, W.~Lamersdorf, K.~Reinhard, and J.W. Schmidt.
\newblock Database Application Support in Open Systems: Language Support and
  Implementation.
\newblock In {\em Proc. IEEE 4th Int. Conf. on Data Engineering}, Los Angeles,
  USA, February 1988.

\bibitem[JK83]{JaKo83}
M.~Jarke and J.~Koch.
\newblock Range Nesting: A Fast Method to Evaluate Quantified Queries.
\newblock In {\em Proceedings of the ACM-SIGMOD International Conference on
  Management of Data}, pages 196--206, May 1983.

\bibitem[JLRS88]{JLRS88}
W.~Johannsen, W.~Lamersdorf, K.~Reinhard, and J.W. Schmidt.
\newblock The DURESS Project: Extending Databases into an Open Systems
  Architecture.
\newblock In {\em Advances in Database Technology, EDBT '88}, volume 303 of
  {\em Lecture Notes in Computer Science}, pages 616--620. Springer-Verlag,
  1988.

\bibitem[JLS85]{JLS85}
M.~Jarke, V.~Linnemann, and J.W. Schmidt.
\newblock Data Constructors: On the Integration of Rules and Relations.
\newblock In {\em 11th Intern. Conference on Very Large Data Bases, Stockholm},
  August 1985.

\bibitem[JMW{\etalchar{+}}90]{JMW*90}
M.~Jeusfeld, M.~Mertikas, I.~Wetzel, Jarke. M., and J.W. Schmidt.
\newblock Database Application Development as an Object Modelling Activity.
\newblock In {\em Proc. 16th VLDB Conference}, Brisbane, Australia, August
  1990.

\bibitem[MS89]{MaSc89}
F.~Matthes and J.W. Schmidt.
\newblock The Type System of {DBPL}.
\newblock In {\em Proceedings of the Second International Workshop on Database
  Programming Languages, Salishan, Oregon}, pages 255--260, June 1989.

\bibitem[MS91]{MaSc91}
F.~Matthes and J.W. Schmidt.
\newblock Towards Database Application Systems: Types, Kinds and Other Open
  Invitations.
\newblock In {\em Proceedings of the Kiev East/West Workshop on Next Generation
  Database Technology}, volume 504 of {\em Lecture Notes in Computer Science},
  April 1991.

\bibitem[MS92]{MaSc92b}
F.~Matthes and J.W. Schmidt.
\newblock DBPL User and System Manual.
\newblock FIDE Technical Report FIDE/92/??, Fachbereich Informatik,
  Universit\"at Hamburg, West Germany, 1992.

\bibitem[MSS91]{MSS91}
F.~Matthes, G.~Schr\"oder, and J.W. Schmidt.
\newblock VAX Modula-2 User's Guide; VAX DBPL User's Guide.
\newblock DBPL Memo 121-91, Fachbereich Informatik, Universit\"at Hamburg, West
  Germany, December 1991.

\bibitem[Sch77]{Schm77a}
J.W. Schmidt.
\newblock Some High Level Language Constructs for Data of Type Relation.
\newblock In {\em Proceedings of the ACM-SIGMOD International Conference on
  Management of Data, Toronto, Canada}, August 1977.

\bibitem[SEM88]{SEM88}
J.W. Schmidt, H.~Eckhardt, and F.~Matthes.
\newblock {DBPL Report}.
\newblock DBPL-Memo 112-88, Fachbereich Informatik, Johann Wolfgang
  Goethe-Universit\"at, Frankfurt, West Germany, 1988.

\bibitem[SGLJ89]{SGLJ89}
J.W Schmidt, L.~Ge, V.~Linnemann, and M.~Jarke.
\newblock Integrated Fact and Rule Management Based on Database Technology.
\newblock In J.W. Schmidt and C.~Thanos, editors, {\em Foundations of Knowledge
  Base Management}, Topics in Information Systems. Springer-Verlag, 1989.

\bibitem[SL85]{ScLi85}
J.W. Schmidt and V.~Linnemann.
\newblock Higher Level Relational Objects.
\newblock In {\em Proc. 4th British National Conference on Databases (BNCOD
  4)}. Cambridge University Press, July 1985.

\bibitem[SM89]{ScMa89}
J.W. Schmidt and F.~Matthes.
\newblock Advances in Database Programming: On Concepts, Languages and
  Methodologies.
\newblock In {\em Proc. 16th SOFSEM'89}, \v{Z}diar, High Tatra, \v{C}SSR,
  December 1989.
\newblock Available through Hamburg University.

\bibitem[SM90a]{ScMa90}
J.W. Schmidt and F.~Matthes.
\newblock {DBPL} Language and System Manual.
\newblock Esprit Project 892 MAP 2.3, Fachbereich Informatik, Universit\"at
  Hamburg, West Germany, April 1990.

\bibitem[SM90b]{ScMa90a}
J.W. Schmidt and F.~Matthes.
\newblock Language Technology for Post-Relational Data Systems.
\newblock In A.~Blaser, editor, {\em Database Systems of the 90s}, volume 466
  of {\em Lecture Notes in Computer Science}, pages 81--114, November 1990.

\bibitem[SM91a]{ScMa91a}
J.W. Schmidt and F.~Matthes.
\newblock Modular and Rule-Based Database Programming in DBPL.
\newblock FIDE Technical Report FIDE/91/15, Fachbereich Informatik,
  Universit\"at Hamburg, West Germany, February 1991.

\bibitem[SM91b]{ScMa90b}
J.W. Schmidt and F.~Matthes.
\newblock Naming Schemes and Name Space Management in the DBPL Persistent
  Storage System.
\newblock In {\em Proceedings of the Fourth International Workshop on
  Persistent Object Systems, Martha's Vineyard, Massachusetts}. Morgan Kaufmann
  Publishers, January 1991.

\bibitem[SWBM89]{SWBM89}
J.W. Schmidt, I.~Wetzel, A.~Borgida, and J.~Mylopoulos.
\newblock Database Programming by Formal Refinement of Conceptual Designs.
\newblock {\em IEEE -- Data Engineering}, September 1989.

\end{thebibliography}