Zettel
Zettel allows taking notes from several references and organizing them
Zettel is a program for taking notes from bibliographic references. Instead of marking the text on paper and then going crazy looking for where the copy ended up, the notes are saved in a database, linked to the reference from where they were copied. Notes can be tagged and retrieved in several ways.
Zettel é um programa para fichamento de referências bibliográficas.