bibview is a tool to let you set up and maintain BibTeX bibliography
databases.  LaTeX can then use these automatically in citations and
bibliographies in your documents.
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From its README:
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   It [bibview] supports the user in making new entries,
   searching for entries and moving entries from one BiB to another.
   It is possible to work with more than one BiB simultaneously.
   bibview is implemented with Xt and Athena Widgets.
   There are several types of windows in bibview:
   The main window contains menus for customizing bibview and
   for working with BiBs on the file level.
   The bibliography window (one for every open BiB) contains commands
   for manipulating the BiB.
   The list window (at most one for every open BiB) shows a list of
   entries. It displays the fields author, title, type and year.
   The card window (at most one for every entry) helps editing an entry.
   It contains boxes for each field of the entry (according to the type).
   The fields can be edited by putting the mouse cursor into the field.
   Macros in fields and the symbol for concatenation ('#') are marked
   with a preceding '@'.

• Igor Vlasenko

• bibview