Synapsen – A hypertextual Card Index

Synapsen is a hypertextual card index or reference organizer, which is to say a storage system on the basis of an electronic literature database that enables the management of bibliographies. However, in contrast to normal literature management software, synapsen offers a very distinct advantage: with catchwords entered by the user, the program connects individual cards automatically and creates not only a network of cards whose relation to each other might have been forgotten, but also creates completely unexpected connections and relations between individual entries. synapsen is therefore not only for electronic literature management, but also a helping hand when writing scientific texts, which participates in communication with the author in order to augment lines of argumentation and the generation of ideas.

Synapsen is a hypertextual card catalog or reference management software written in JAVA, that is housed on a SQL-database based in the literature networking structure from Niklas Luhmann.


  • Concept
  • ScreenShots
  • Forum
  • References

»I'm sure I read that before. Where was it again?« is the common, always returning question of every reader, and this is the point where Synapsen takes its position. Not only researchers and students of the sciences that rely on the written word are able to recognise this classical problem which this card-catalog seeks to remedy: Forgetting. How is it possible in the framework of a (text-based) scientific report to position the researched, reformulated piles of knowledge to the extent that even years later it is something that you have at your disposal?

Synapsen is for literature management that is specifically different from market-softare like ask-sam, Lidos, LiMan, EndNote etc. Besides simply managing bibliographic data, Synapsen also creates an information-architecture that grants the card-catalog the role of an author. Every dataset, which contains not only the bibliographic information pertaining to a text but also complete literature reports, is characterized by a list of catchwords. These are added by the user during the data-entry stage of a card. With the assistance of thorough internal comparisons, Synapsen finds cards that share catchwords. Every card is registered in a network of its own knowledge, which can be hypertextually tracked by the mouse-clicking user. In this way, the card catalog delivers unexpected connections and associates lines of argumentation via terms and relevant texts/locations that might not be seen or considered by the user — perhaps it was even forgotten. The card catalog in fact becomes an autonomous communication partner and helping hand of its own.

Here you'll find some screen shots of the program and its features and functions. Simply click on the image on the left in order to start a slide show.

Among the features shown are, e.g., the bibliography function, the printing interface including the feature to print 'real' index cards on paper, and, last but not least, the new features of version 4.0, i.e. the timeline tool and the mind map.

The program is targeted at students and scientists that have to manage a large body of literature. First and foremost it is dedicated to researchers and students in the humanities and sciences, especially philologists in every language, art history, social- and cultural studies, philosophy etc., scholars and historians in general, but also business, library, information and communication scientists or lawyers and all those who maintain a bibliography over a long period of time.

The Mailinglist of Synapsen

In order to subscribe to the mailing list of synapsen enter your e-mail address in the formular below and then click on the logo:

Subscribe on Synapsen's mailing list.

You may also be interested in checking the Archive of Synapsen's mailing list, including solutions and discussions of the daily work with the card index.

Further Reading

Krajewski, Markus, 2011. Paper Machines. About Cards & Catalogs, 1548–1929, History and Foundations of Information Science, The MIT Press, Cambridge, Mass.

Krajewski, Markus, 2003. Elektronische Literaturverwaltungen. Kleiner Katalog von Merkmalen und Möglichkeiten, in: Norbert Franck and Joachim Stary (Eds.), Technik wissenschaftlichen Arbeitens (= UTB), 11., completely revised Ed., Ferdinand Schöningh Verlag, Paderborn, p. 97--115 (enhanced version as pdf-Datei Bib)

Luhmann, Niklas, 1993. Kommunikation mit Zettelkästen. Ein Erfahrungsbericht.In: André Kieserling (Ed.), Universität als Milieu, p. 53-61. Haux, Bielefeld.

Synapsen are recommended by:

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zum Artikel [© F.A.Z.]




Current Version 4.3.7, 19.11.2018

Since the first release of Synapsen 1.0 in October 1999 the program has been continuously developed, improved and enhanced. The current Version 4.3.7 is dated from 2018/11/19.


Some Features of the Program

  • Runs on all current operating systems (Windows, Mac OS X, Linux, Unix) and even on USB-Sticks.
  • Automatic or individual connections between all cards through common headwords.
  • Easy editing, searching and viewing of reference entries.
  • Direct connection to MS Word and Open Office 3.0 in order to support footnote insertion by one click
  • Direct search and download from OPACs like Library of Congress, Bibliothèque Nationale, or GBV via the z39.50 interface.
  • Extensive printing interface
  • Embedding of your pdf, html-, txt-, rtf-documents as well as images
  • Produces fully BibTeX compliant output, tight connection to LaTeX, but also to word processors via RTF and copy & paste.
  • Many individual formatting features while creating the bibliographical output
  • Data import and export via BibTeX, PDF and RTF, RefWorks and Citavi.
  • Support of the biblatex package
  • Complete support of Unicode, i.e. you can simultaneosly work with many different alphabets like cyrillic, hebrew or chinese etc.
  • Support of SQL for the internal database server in order to procure future compatibility of your data. Linkage to external databases like mySQL also possible.
  • A network version of Synapsen is available which supports editing of one online-database for many remote researchers.





Verantwortlich für den Inhalt gemäss § 5 TMG i. V. m. § 55 RStV:

Angaben gemäß § 5 TMG und verantwortlich für den Inhalt nach § 55 Abs. 2 RStV:

Prof. Dr. Markus Krajewski
Bauhaus-Universität Weimar
Bauhausstr. 11
99423 Weimar
Telephon: +49 3643 58-3840

Der Nutzung von im Rahmen der Impressumspflicht veröffentlichten Kontaktdaten durch Dritte, um nicht angeforderte Werbung und Information zuzusenden, wird ausdrücklich widersprochen.


Für Inhalt und Funktion bei Links auf fremde Webseiten wird keine Haftung übernommen.


Downloads und Kopien dieser Seiten sind für den privaten Gebrauch gestattet, für den kommerziellen Gebrauch nicht gestattet. Die Inhalte unterliegen dem deutschen Urheberrecht. Vervielfältigung, Bearbeitung, Verbreitung und jede Art der Verwertung außerhalb der Grenzen des Urheberrechtes bedürfen der schriftlichen Zustimmung des Autors. Soweit die Inhalte auf dieser Seite nicht vom Betreiber erstellt wurden, werden die Urheberrechte Dritter beachtet. Inhalte Dritter sind als solche gekennzeichnet. Sollte eine Urheberrechtsverletzung zu finden sein, bitte ich um einen entsprechenden Hinweis.


In dringenden Fragen zur Software können Sie sich an Markus Krajewski unter wenden.

Siehe auch und

CD-ROM-Version bestellen

Auf Wunsch können Sie auch eine CD-ROM mit dem kompletten Programm erhalten, auf der sich neben der jeweils aktuellsten Version von synapsen eine JAVA Virtuelle Maschine, ein vollständiges MikTeX-Paket sowie passende Datenbanktreiber befinden, überweisen Sie dazu bitte €5,-- für CD, Porto und Versandkosten an:

Markus Krajewski
Konto 7987250
Netbank, BLZ 20090500

Zudem sollten Sie eine kurze E-Mail mit Ihrer Lieferanschrift an senden, Sie bekommen dann umgehend die CD-ROM zugeschickt.

Sie können aber auch €5,--, ebenfalls mit einer kurzen Nachricht auf mein PayPal-Konto einzahlen, einfach auf das Logo klicken und den Anweisungen folgen: