\begin{thebibliography}{}

\bibitem[\protect\citeauthoryear{Ackerman and Fielding}{1995}]{AckFie95}
Ackerman, M.S. and Fielding, R.T.
\newblock Collection maintenance in the digital library.
\newblock In {\em Proceedings of the Second Annual Conference on the Theory and
  Practice of Digital Libraries}, June 1995.

\bibitem[\protect\citeauthoryear{Balabanovic and Shoham}{1995}]{BalSho95}
Balabanovic, M. and Shoham, Y.
\newblock Learning inforamtion retrieval agents: Experiments with automated web
  browsing.
\newblock In {\em Proceedings of the AAAI Spring Symposium on Information
  Gathering from Heterogeneous, Distributed Resources}, March 1995.

\bibitem[\protect\citeauthoryear{Birmingham}{1995}]{Bir95}
Birmingham, W.P.
\newblock An agent-based architecture for digital libraries.
\newblock In {\em Proceedings of the Second Annual Conference on the Theory and
  Practice of Digital Libraries}, June 1995.

\bibitem[\protect\citeauthoryear{B{\"o}hm and Rakow}{1994}]{BoeRak94}
B{\"o}hm, K. and Rakow, T.C.
\newblock Metadata for multimedia documents.
\newblock {\em Sigmod Record}, 23(4):21--26, December 1994.

\bibitem[\protect\citeauthoryear{Broglio \bgroup \em et al.\egroup
  }{1994}]{bcc94}
Broglio, J., Callan, J.P., and Croft, W.B.
\newblock Inquery system overview.
\newblock In {\em Proceedings of the TIPSTER Text Programm (Phase 1)}, pages
  47--67. Morgan Kaufmann Publishers, 1994.

\bibitem[\protect\citeauthoryear{Callan \bgroup \em et al.\egroup
  }{1991}]{cch92}
Callan, J.P., Croft, W.B., and Harding, S.M.
\newblock The {I}nquery retrieval system.
\newblock In {\em Proceedings of the Third International Conference on Database
  and Expert Systems}, 1991.

\bibitem[\protect\citeauthoryear{Cameron}{1994}]{Cam94}
Cameron, R.D.
\newblock To link or to copy? {F}our principles for materials acquisition in
  internet electronic libraries.
\newblock Technical Report CMPT TR 94-08, School of Computing Science, Simon
  Fraser University, December 1994.

\bibitem[\protect\citeauthoryear{Cardelli}{1989}]{Card89}
Cardelli, L.
\newblock Typeful programming.
\newblock Technical Report~45, Digital Equipment Corporation, Systems Research
  Center, Palo Alto, California, May 1989.

\bibitem[\protect\citeauthoryear{Cousins \bgroup \em et al.\egroup
  }{1995}]{CouKetPae+95}
Cousins, S., Ketchpel, S., Paepcke, A., Garcia-Molina, H., Hassan, S., and
  R{\"o}scheisen, M.
\newblock Interpay: Managing multiple payment mechanisms in digital libraries.
\newblock In {\em Proceedings of the Second Annual Conference on the Theory and
  Practice of Digital Libraries}, 1995.

\bibitem[\protect\citeauthoryear{Dearle}{1989}]{Dea89}
Dearle, A.
\newblock Environments: a flexible binding mechanism to support system
  evolution.
\newblock In {\em Proc. HICSS-22, Hawaii}, volume~II, pages 46--55, January
  1989.

\bibitem[\protect\citeauthoryear{Garcia-Molina \bgroup \em et al.\egroup
  }{1995}]{GarHamIre+95}
Garcia-Molina, H., Hammer, J., Ireland, K., Papakonstantinou, Y., Ullman, J.,
  and Widom, J.
\newblock Integrating and accessing heterogeneous information sources in
  tsimmis.
\newblock In {\em Proceedings of the AAAI Symposium on Information Gathering},
  pages 61 --64, Stanford, California, March 1995.

\bibitem[\protect\citeauthoryear{Gosling and {McG}ilton}{1995}]{GMcG95}
Gosling, J. and {McG}ilton, H.
\newblock The {Java} language environment --- {A} whitepaper.
\newblock Technical report, Sun Microsystems, October 1995.

\bibitem[\protect\citeauthoryear{Graham}{1995}]{Gra95}
Graham, P.S.
\newblock The digital research library: {T}asks and commitments.
\newblock In {\em Proceedings of the Second Annual Conference on the Theory and
  Practice of Digital Libraries}, June 1995.

\bibitem[\protect\citeauthoryear{Hammer and McLeod}{1993}]{HamMcL93}
Hammer, J. and McLeod, D.
\newblock An approach to resolving semantic heterogeneity in a federation of
  autonomous heterogeneous database systems.
\newblock {\em International Journal of Intelligent and Cooperative Information
  Systems}, 2(1):51 -- 83, March 1993.
\newblock 5.

\bibitem[\protect\citeauthoryear{Kashyap \bgroup \em et al.\egroup
  }{1996}]{KasShaShe96}
Kashyap, V., Shah, K., and Sheth, A.
\newblock Metadata for building the mutimedia patchquilt.
\newblock In Subrahmenian, V.S. and Jajodia, S., editors, {\em Multimedia
  Database Systems}, pages 297--319. Springer, 1996.

\bibitem[\protect\citeauthoryear{Kirby \bgroup \em et al.\egroup
  }{1996}]{KCMS96}
Kirby, G.N.C., Connor, R.C.H., Morrison, R., and Stemple, D.
\newblock Using reflection to support type-safe evolution in persistent
  systems.
\newblock Technical Report CS/96/10, University of St.~Andrews, 1996.

\bibitem[\protect\citeauthoryear{Li \bgroup \em et al.\egroup
  }{1996}]{LiGauGau+96}
Li, W., Gauch, S., Gauch, J., and Pua, K.M.
\newblock Vision: A digital video library.
\newblock In {\em Digital Libraries '96, 1st ACM International Conference on
  Digital Libraries}, 1996.

\bibitem[\protect\citeauthoryear{Mathiske \bgroup \em et al.\egroup
  }{1995a}]{MMS95a}
Mathiske, B., Matthes, F., and Schmidt, J.W.
\newblock On migrating threads.
\newblock In {\em Proceedings of the Second International Workshop on Next
  Generation Information Technologies and Systems, Naharia, Israel}, June 1995.
\newblock (Also appeared as TR FIDE/95/136).

\bibitem[\protect\citeauthoryear{Mathiske \bgroup \em et al.\egroup
  }{1995b}]{MMS95b}
Mathiske, B., Matthes, F., and Schmidt, J.W.
\newblock Scaling database languages to higher-order distributed programming.
\newblock In {\em Proceedings of the Fifth International Workshop on Database
  Programming Languages, Gubbio, Italy}. Springer-Verlag, September 1995.
\newblock (Also appeared as TR FIDE/95/137).

\bibitem[\protect\citeauthoryear{Mathiske \bgroup \em et al.\egroup
  }{1996}]{MMS96b}
Mathiske, B., Matthes, F., and Schmidt, J.W.
\newblock On migrating threads.
\newblock To appear in the Journal of Intelligent Information Systems, 1996.

\bibitem[\protect\citeauthoryear{Matthes and Schmidt}{1991}]{MaSc91b}
Matthes, F. and Schmidt, J.W.
\newblock Bulk types: Built-in or add-on?
\newblock In {\em Database Programming Languages: Bulk Types and Persistent
  Data}. Morgan Kaufmann Publishers, September 1991.

\bibitem[\protect\citeauthoryear{Matthes and Schmidt}{1992}]{MaSc92a}
Matthes, F. and Schmidt, J.W.
\newblock Definition of the {Tycoon} language {TL} -- a preliminary report.
\newblock Informatik Fachbericht FBI-HH-B-160/92, Fachbereich Informatik,
  Universit\"at Hamburg, Germany, November 1992.

\bibitem[\protect\citeauthoryear{Matthes and Schmidt}{1993}]{MaSc93b}
Matthes, F. and Schmidt, J.W.
\newblock System construction in the {Tycoon} environment: Architectures,
  interfaces and gateways.
\newblock In Spies, P.P., editor, {\em Proceedings of Euro-Arch'93 Congress},
  pages 301--317. Springer-Verlag, October 1993.

\bibitem[\protect\citeauthoryear{Matthes and Schmidt}{1994}]{MaSc94}
Matthes, F. and Schmidt, J.W.
\newblock Persistent threads.
\newblock In {\em Proceedings of the Twentieth International Conference on Very
  Large Data Bases, VLDB}, pages 403--414, Santiago, Chile, September 1994.

\bibitem[\protect\citeauthoryear{Matthes \bgroup \em et al.\egroup
  }{1995}]{MSS95}
Matthes, F., Schr{\"o}der, G., and Schmidt, J.W.
\newblock {Tycoon}: A scalable and interoperable persistent system environment.
\newblock In Atkinson, M.P., editor, {\em Fully Integrated Data Environments}.
  Springer-Verlag (to appear), 1995.

\bibitem[\protect\citeauthoryear{Matthes \bgroup \em et al.\egroup
  }{1996}]{MMS96a}
Matthes, F., M{\"u}ller, R., and Schmidt, J.W.
\newblock Towards a unified model of untyped object stores: Experience with the
  {Tycoon} store protocol.
\newblock In {\em Advances in Databases and Information Systems (ADBIS'96),
  Proceedings of the Third International Workshop of the Moscow ACM SIGMOD
  Chapter}, 1996.

\bibitem[\protect\citeauthoryear{Matthes}{1993}]{Matt93}
Matthes, F.
\newblock {\em Persistente Objektsysteme: Integrierte Datenbankentwicklung und
  Programmerstellung}.
\newblock Springer-Verlag, 1993.
\newblock (In German).

\bibitem[\protect\citeauthoryear{McNab \bgroup \em et al.\egroup
  }{1996}]{McNSmiWit+96}
McNab, R.J., Smith, L.A., Witten, I.H., and Henderson, C.L.
\newblock Towards the music library: {T}une retrieval from acoustic input.
\newblock In {\em Digital Libraries '96, 1st ACM International Conference on
  Digital Libraries}, 1996.

\bibitem[\protect\citeauthoryear{Meyer}{1990}]{Meyer90}
Meyer, B.
\newblock Lessons from the design of the {Eiffel} libraries.
\newblock {\em Communications of the ACM}, 33(9):69--88, September 1990.

\bibitem[\protect\citeauthoryear{Meyer}{1994}]{Meyer94}
Meyer, B.
\newblock {\em The Base Object-oriented Component Libraries}.
\newblock Prentice Hall, Englewood Cliffs, New Jersey, 1994.

\bibitem[\protect\citeauthoryear{Morrison \bgroup \em et al.\egroup
  }{1990}]{MABD90}
Morrison, R., Atkinson, M.P., Brown, A.L., and Dearle, A.
\newblock On the classification of binding mechanisms.
\newblock {\em Infomation Processing Letters}, 34(2):51--55, 1990.

\bibitem[\protect\citeauthoryear{Morrison \bgroup \em et al.\egroup
  }{1994}]{MBC*94}
Morrison, R., Brown, A.L., Connor,\newblock R.C.H., Cutts, Q.J., Dearle, A., Kirby,
  G.N.C., and Munro, D.S.
\newblock The {Napier88} reference manual (release 2.0).
\newblock FIDE Technical Report Series FIDE/94/104, FIDE Project Coordinator,
  Department of Computing Sciences, University of Glasgow, Glasgow G128QQ,
  1994.

\bibitem[\protect\citeauthoryear{Nieder\'ee \bgroup \em et al.\egroup
  }{1996}]{MNS96}
Nieder\'ee, C., Hattendorf, C., M\"u{\ss}ig, S., Warnke, M., and Schmidt, J.W.
\newblock Warburg electronic library: Eine digitale {B}ibliothek f\"ur die
  {P}olitische {I}konographie.
\newblock {\em unihh forschung}, XXXI, 1996.

\bibitem[\protect\citeauthoryear{N{\"u}rnberg \bgroup \em et al.\egroup
  }{1995}]{NueFurLeg+95}
N{\"u}rnberg, P.J., Furuta, R., Leggett, J.L., Marshall, C.C., and Shipman~III,
  F.M.
\newblock Digital libraries: Issues and architectures.
\newblock In {\em Proceedings of the Second Annual Conference on the Theory and
  Practice of Digital Libraries}, June 1995.

\bibitem[\protect\citeauthoryear{Paepcke}{1996}]{Pae96}
Paepcke, A.
Digital libraries: Searching is not\newblock enough.
\newblock {\em D-Lib Magazine}, May 1996.
\newblock http://ukoln.bath.ac.uk/ dlib/dlib/may96.

\bibitem[\protect\citeauthoryear{R{\"o}scheisen \bgroup \em et al.\egroup
  }{1994}]{RoeMogWin94}
R{\"o}scheisen, M., Mogensen, C., and Winograd, T.
\newblock Shared web annotations as a platform for third-party value-added
  information providers: Architecture, protocols, and usage examples.
\newblock Technical Report CSDTR/DLTR, Computer Science Department, Stanford
  University, Stanford, CA 94305, U.S.A., November 1994.
\newblock http://www-pcd.stanford.edu/COMMENTOR.

\bibitem[\protect\citeauthoryear{R{\"o}scheisen \bgroup \em et al.\egroup
  }{1995}]{RoeWinPae95}
R{\"o}scheisen, M., Winograd, T., and Paepcke, A.
\newblock Content ratings and other third-party value-added information -
  defining an enabling platform.
\newblock {\em D-Lib Magazine}, August 1995.
\newblock http://ukoln.bath.ac.uk/dlib/dlib/august95.

\bibitem[\protect\citeauthoryear{Rudloff \bgroup \em et al.\egroup
  }{1995}]{RMS95}
Rudloff, A., Matthes, F., and Schmidt, J.W.
\newblock Security as an add-on quality in persistent object systems.
\newblock In {\em Second International East/West Database Workshop, Klagenfurt,
  Austria}, Workshops in Computing, pages 90--108. Springer-Verlag, 1995.
\newblock (Also appeared as TR FIDE/95/138).

\bibitem[\protect\citeauthoryear{Schmidt and Matthes}{1993}]{ScMa93}
Schmidt, J.W. and Matthes, F.
\newblock Lean languages and models: Towards an interoperable kernel for
  persistent object systems.
\newblock In {\em Proceedings of the IEEE International Workshop on Research
  Issues in Data Engineering}, pages 2--16, April 1993.

\bibitem[\protect\citeauthoryear{Schmidt and Matthes}{1994}]{ScMa94}
Schmidt, J.W. and Matthes, F.
\newblock The {DBPL} project: Advances in modular database programming.
\newblock {\em Information Systems}, 19(2):121--140, 1994.

\bibitem[\protect\citeauthoryear{Schmidt \bgroup \em et al.\egroup
  }{1993}]{SMV93}
Schmidt, J.W., Matthes, F., and Valduriez, P.
\newblock Building persistent application systems in fully integrated data
  environments: Modularization, abstraction and interoperability.
\newblock In {\em Proceedings of Euro-Arch'93 Congress}, pages 270--287.
  Springer-Verlag, October 1993.

\bibitem[\protect\citeauthoryear{Schmidt}{1977}]{Schm77a}
Schmidt, J.W.
\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[\protect\citeauthoryear{Shivakumar and Garcia-Molina}{1996}]{ShiGar96}
\newblock Shivakumar, N. and Gar\-cia-Molina, H.
\newblock Building a scalable and accurate copy detection mechanism.
\newblock In {\em Digital Libraries '96, 1st ACM International Conference on
  Digital Libraries}, 1996.

\bibitem[\protect\citeauthoryear{Stemple \bgroup \em et al.\egroup
  }{1991}]{SMA91}
Stemple, D., Morrison, R., and M., Atkinson.
\newblock Type-safe linguistic reflection.
\newblock In {\em Database Programming Languages: Bulk Types and Persistent
  Data}, pages 357--362. Morgan Kaufmann Publishers, 1991.

\bibitem[\protect\citeauthoryear{Stemple \bgroup \em et al.\egroup
  }{1992}]{SSF92}
Stemple, D., Sheard, T., and Fegaras, L.
\newblock Linguistic reflection: A bridge from programming to database
  languages.
\newblock In {\em Proceedings 25th Annual Hawaii International Conference on
  System Sciences}, pages 46--55, 1992.

\bibitem[\protect\citeauthoryear{Tycoon}{1992}]{Tyco92X}
{WWW} home page for the {Tycoon} project.\newline
  http://\-idom-www.\-informatik.\-uni-hamburg.de/Projects/\-Tycoon/\-entry.html, 1992.

\bibitem[\protect\citeauthoryear{Van~House}{1995}]{Hou95}
Van~House, N.A.
\newblock User needs assessment and evaluation for the uc berkeley electronic
  environmental library project: a preliminary report.
\newblock In {\em Proceedings of the Second Annual Conference on the Theory and
  Practice of Digital Libraries}, School of Library and Information Studies
  University of California Berkeley, CA 94720-4600, USA, June 1995.
\newblock Austin, Texas, USA.

\end{thebibliography}
