Reference linking tools described previously provide complementary services. How can we combine these services? Some recent initiatives:

• Reference linking API (Donna Bergmark and Carl Lagoze, Cornell U., OpCit project): builds database of 'surrogate' documents by collecting metadata and bibliographic data from archives that run OAi Dienst servers, Java-based for non-Dienst servers
• OpenURL (Herbert van de Sompel): proposed open specification to allow 'context-sensitive' services to be added to Web-wide search/browse, e.g. provide reference links to local library holdings. Part of the SFX framework
• Linkbaton (Openly Informatics, Inc.): users can select preferred content providers
• ResearchIndex (NEC): source code available for non-commercial use