Comparison of reference management software
From Wikipedia, the free encyclopedia
The following tables compare notable reference management software. The comparison includes older applications that may no longer be supported, as well as actively-maintained software.
General
In the "notes" section, there is a difference between:
- web-based, referring to applications that may be installed on a web server (usually requiring MySQL or another database and PHP, Perl, Python, or some other language for web applications), and;
- a centrally hosted website.
| Software | Developer | First public release | Latest stable release date | Latest stable version | Cost (USD) | Free software | License | Notes |
|---|---|---|---|---|---|---|---|---|
| BibBase | Christian Fritz | 2005 | 2024-06-06 | ? | Free for students / Paid plan for others | No | Proprietary | Centrally hosted website, intended for publication pages |
| BibDesk | BibDesk developers | 2002-04 | 2026-01-19 | 1.9.10 | Free | Yes | BSD | BibTeX front-end + repository; Cocoa-based; integration with Spotlight |
| BibSonomy | University of Kassel | 2006-01 | 2024-01-08 | 4.1.0 | Free | Yes | AGPL, GPL, LGPL[1] | Centrally hosted website |
| Bookends | Sonny Software | 1988 (Mac) / 1983 (Apple II+) | 2023-05-06 | 14.2[2] | US$59.99[a] | No | Proprietary | Desktop & iOS synced via iCloud, integrated web search, PDF download, auto-completion, Word plugin, BibTex support, PDF annotations stored as notes |
| Citavi | Lumivero | 2006-02-13 | 2023-08-15 | 6.17.0.0 | US$89-1947[b] | No | Proprietary | Data can be saved locally on the computer, or, for team access, in the Citavi Cloud or an intranet Microsoft SQL Server;[3] search databases from interface[4] |
| CiteMe | Daniel nichiata | 2023 | Continually updated online | Free / Paid plan | No | Proprietary | Centrally hosted website; academic citation generator; searches 8+ databases (OpenAlex, Semantic Scholar, PubMed, Europe PMC, SciELO, CORE, CrossRef); 40+ citation styles (ABNT, APA, MLA, Chicago, IEEE, Vancouver, and others); BibTeX and RIS export; browser extension (Chrome, Firefox) | |
| EndNote | Clarivate Analytics | 1988 | 2025-04-22 | 2025 | US$299.95[a] | No | Proprietary | The web version EndNote basic (formerly, EndNote Web) is free of charge |
| JabRef | JabRef developers | 2003-11-29 | 2024-07-11 | 5.15 | Free | Yes | MIT license | Java BibTeX and BibLaTeX manager |
| KBibTeX | KBibTeX developers | 2005-08 | 2020-04-26 | 0.9.2 | Free | Yes | GNU GPL | BibTeX front-end, using the KDE Software Compilation |
| Mendeley | Elsevier | 2008-08 | 2025-06-05 | 2.135.0 | Free / Online storage free up to 2 GB / Additional storage space available | No | Proprietary with public API | Account required, app versions for web, Windows, Linux, macOS. Data synced automatically between clients and server. Usable offline. |
| Paperpile | Stefan Washietl, Gregorgy Jordan, Andreas Gruber | 2013 | Continually updated online | US$2.99/month for academics, 9.99/month otherwise | No | Proprietary | Web-app, integrates with Google Docs, collaboration & sharing features, currently only on Google Chrome | |
| Papers | ReadCube | 2011-10 | 2023-04-04 | v.4.35.2224 | US$ 3/month for students, 5/month academics | No | Proprietary | Web-app, Desktop (MacOS, Windows), Mobile (iOS and Android). Microsoft Word and Google Docs add-in. Browser extension (Chrome, Firefox, Edge, Safari) |
| refbase | refbase developers | 2003-06-03 | 2014-02-28 | 0.9.6 | Free | Yes | GNU GPL | Web-based for institutional repositories/self-archiving[5] |
| RefDB | refdb developers | 2001-04-25 | 2022-02-13 | 1.0.3 | Free | Yes | GNU GPL | Network-transparent; XML/SGML bibliographies |
| RefWorks | Ex Libris / ProQuest / Clarivate | 2001 | 2024-07-09 | 4.6 | Institutional subscription | No | Proprietary | Web-based, browser-accessed, Word & Google Docs |
| Zotero | Corporation for Digital Scholarship | 2006 | 2026-02-03 | 8.0.2[6] | Free / Online storage free up to 300 MB / Additional storage space available | Yes | AGPL | Native desktop and mobile applications and web browser connectors. Browser access through Zotero.org or cloud-based database folder on a user's computer (Google Drive, Dropbox, etc.). |
Operating system support
In the case of web applications, this describes the server OS. For centrally hosted websites that are proprietary, this is not applicable. Any client OS can connect to a web service unless stated otherwise in a footnote.
| Software | Windows | macOS | Linux | ChromeOS | BSD | Unix | iOS App | Android App | Windows App |
|---|---|---|---|---|---|---|---|---|---|
| Bebop | Yes | Yes | Yes | ? | Yes | Yes | No | No | No |
| BibBase | N/a | N/a | N/a | N/a | N/a | N/a | ? | ? | ? |
| BibDesk | No | Yes | No | No | No | No | No | No | No |
| BibSonomy | N/a | N/a | N/a | N/a | N/a | N/a | ? | ? | ? |
| Bookends | No | Yes | No | ? | No | No | Yes | ? | ? |
| Citavi | Yes | No | No | No | No | No | No | No | No |
| EndNote | Yes | Yes | No | No | No | No | Yes | No | No |
| JabRef | Yes | Yes | Yes | No | No | Yes | No | No | No |
| KBibTeX | Experimental | Experimental | Yes | ? | Yes | Yes | No | No | No |
| Mendeley | Yes | Yes | Yes | No | No | No | No (phased out as of March 15, 2021)[7] |
No (phased out as of March 15, 2021)[7] |
No |
| Paperpile | Yes | Yes | Yes | Yes | No (requires Chromium) |
No (requires Chromium) |
Yes[8] | Yes[9] | No |
| Papers | Yes | Yes | No | Yes | No | No | Yes | Yes | Yes |
| Pybliographer | Partial[c] | Partial[c] | Yes | ? | Yes | Yes | No | No | No |
| refbase | Yes | Yes | Yes | Yes | Yes | Yes | No | No | No |
| RefDB | Yes | Yes | Yes | ? | Yes | Yes | No | No | No |
| RefWorks[10] | Yes | Yes | No | Yes | Yes | ? | No | ? | No |
| Zotero | Yes | Yes | Yes | Intel only | No | Yes | Yes | Yes | Yes |
Export file formats
This table lists the machine-readable file formats that can be exported from reference managers. These are typically used to share data with other reference managers or with other people who use a reference manager. To exchange data from one program to another, the first program must be able to export to a format that the second program may import. Import file formats are in a table below this one.
| Software | BibTeX | Endnote/Refer/BibIX | Medline | MODS XML | RIS | Other |
|---|---|---|---|---|---|---|
| Bebop | Yes | No | No | No | No | unAPI |
| BibBase | Yes | No | No | No | No | None |
| BibDesk | Yes | No | Yes | Yes | Yes | Endnote XML, user customizable |
| BibSonomy | Yes | Yes | No | No | Yes | Various[11] |
| Bookends | Yes | Yes | Yes | No | Yes | Various user-customizable |
| Citavi | Yes | Yes | Yes | Yes | Yes | NVivo and various others |
| EndNote | Yes | Yes | Yes | No | Yes | Various[12] |
| JabRef | Yes | Yes | No | Yes | Yes | BibTeXML, DocBook, HTML, OpenDocument for OO.o, RTF, SQL database, user-customizable |
| KBibTeX | Yes | Yes | No | Depends[d] | Yes | PDF, PostScript, HTML, XML, RTF |
| Mendeley | Yes | Yes | No | No | Yes | Endnote XML |
| Paperpile | Yes | No | No | No | Yes | CSV,JSON |
| Papers | Yes | Yes | No | No | Yes | None |
| Pybliographer | Yes | Yes | Yes | No | No | Ovid |
| refbase | Yes | Yes | No | Yes | Yes | COinS, OpenDocument for OO.o, SRW XML via SRU, unAPI, Word XML |
| RefDB | Yes | Yes | No | Yes | Yes | SRW XML via SRU web service, DocBook, TEI |
| RefWorks | Yes | Yes | No | Yes | Yes | RIS, BibTeX, Tab delimited or XML metadata |
| Zotero | Yes | Yes | As of version 4.0[13] | Yes | Yes | COinS, CSV, Several RDF format standards, TEI, Wikipedia citation templates, Endnote XML, CSL JSON, Refer/BiblX, RefWorks tagged |
Import file formats
This table lists the file formats which may be manually imported into the reference managers without needing to connect to one particular database. Many of these database companies use the same name for their file format as they do for their database (including Copac, CSA, ISI, Medline, Ovid, PubMed, and SciFinder). For the ability to retrieve citations from the particular databases (rather than the file format), please refer to the database connectivity table that is below this table.
As of January 2021[update], CSL YAML is not supported by any reference management system.[14]
| Software | BibTeX | Copac | CSA | Endnote/Refer/BibIX | ISI | Medline | MODS XML | Ovid | PubMed | RIS | SciFinder | Other |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Bebop | Yes | No | No | No | No | No | No | No | No | No | No | None |
| BibBase | Yes | No | No | No | No | No | No | No | No | No | No | None |
| BibDesk | Yes | Yes | No | Yes | Yes | Yes | Yes | No | Yes | Yes | Yes | MARC, JSTOR, Reference Miner |
| BibSonomy | Yes | No | No | Yes | No | No | No | No | No | No | No | Firefox bookmarks |
| Bookends | Yes | Yes | Yes | Yes | Yes | Yes | No | Yes | Yes | Yes | Yes | Various user-customizable |
| Citavi | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Various |
| EndNote | No | No | Yes | Yes | Yes | Yes | No | Yes | Yes | Yes | Yes | Various[15] |
| JabRef | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | BibTexML, Biomail, Inspec, JSTOR, MSBib, PDF widh XMP annotations, REPEC (NEP), SilverPlatter, SixPack |
| KBibTeX | Yes | No | No | Yes | No | No | Depends[d] | No | Yes | Yes | No | None |
| Mendeley | Yes | No | No | Yes | No | No | No | No | No | Yes | No | Browser bookmarks |
| Paperpile | Yes | No | No | Yes | Yes | Yes | No | No | Yes | Yes | No | PDF, MARC |
| Papers | Yes | No | No | Yes | No | No | No | No | Yes | Yes | No | |
| Pybliographer | Yes | No | No | Yes | Yes | Yes | No | Yes | No | No | No | None |
| refbase | Yes | Yes | Yes | Yes | Yes | Yes | Yes | No | Yes | Yes | Yes | RefWorks |
| RefDB | Yes | Yes[d] | No | Yes[d] | Yes[d] | Yes | Yes | No | Yes | Yes | Yes[d] | MARC, risx |
| RefWorks | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Various[16] |
| Zotero | Yes | No[e] | No[e] | Yes | Yes | Yes | Yes | Yes | Yes | Yes | No | COinS, MARC, RDF, unAPI, Browser bookmarks, Endnote XML, others[17] |
Citation styles
| Software | APA | Chicago/Turabian | Harvard | MLA | Other | Extension method |
|---|---|---|---|---|---|---|
| Bebop | No | No | No | No | No | No |
| BibBase | Yes | No | No | No | No | No |
| BibDesk | Yes | Yes | Yes | Yes | Various[18] | BibTeX style files (use Pandoc § CiteProc for CSL[19]) or BibDesk export templates[18] |
| BibSonomy | Yes | No | Yes | No | No | No |
| Bookends | Yes | Yes | Yes | Yes | Various[citation needed] | ? |
| Citavi | Yes | Yes | Yes | Yes | Various[20] | Citavi format (through GUI), includes conditions and programmable components;[20] BibTeX or BibLaTeX when used with LaTeX (use Pandoc § CiteProc for CSL[19]) |
| EndNote | Yes | Yes | Yes | Yes | Various[12] | EndNote format (through GUI)[12] |
| JabRef | Yes | Yes | Yes | Yes | Various | BibTeX style files or BibLaTeX (use Pandoc § CiteProc for CSL[19]) |
| KBibTeX | Yes | Yes | Yes | Yes | Various | BibTeX style files (use Pandoc § CiteProc for CSL[19]) |
| Mendeley | Yes | Yes | Yes | Yes | Various[21] | CSL[21] |
| Paperpile | Yes | Yes | Yes | Yes | Various[21] | CSL[21] |
| Papers | Yes | Yes | Yes | Yes | Various[21] | CSL; BibTeX or BibLaTeX when used with LaTeX[22] |
| Pybliographer | Yes | No | No | No | None | Pybliographer XML |
| refbase | Yes | Yes | Yes | Yes | Various polar & marine journals | PHP |
| RefDB | Yes | Yes | Yes | Yes | 21 biomedical & law journals[23] | XML (citestylex.dtd), interactive script |
| RefWorks | Yes | Yes | Yes | Yes | Various | RefWorks format (through GUI);[24] CSL[21] |
| Zotero | Yes | Yes | Yes | Yes | Various[21] | CSL;[21] BibTeX or BibLaTeX when used with LaTeX[25] |
Reference list file formats
EndNote is incompatible with LaTeX. Among other things, it does not provide for robust citation keys.
| Software | HTML | LaTeX[f] | RTF | Plain text | RSS | Other |
|---|---|---|---|---|---|---|
| Bebop | Yes | No | No | No | Yes | unAPI |
| BibBase | Yes | No | No | No | Yes | No |
| BibDesk | Yes | Yes | Yes | Yes | Yes | Atom, DOC, PDF, XML, |
| BibSonomy | Yes | No | Yes | Yes | Yes | OpenOffice-CSV |
| Bookends | Yes | No | Yes | Yes | No | Clipboard |
| Citavi | Yes | Yes[g] | Yes | Yes | No | Clipboard, DOC, ODT, PDF, HTML |
| EndNote | Yes | No | Yes | Yes | No | Clipboard, XML |
| JabRef | Yes | Yes | Yes | Yes | No | Clipboard |
| KBibTeX | Yes | No | Yes | No | No | PDF, PS |
| Mendeley | Yes | Yes[h] | Yes | Yes | Yes | Clipboard, embeddable HTML widget, RSS |
| Paperpile | Yes | Yes | Yes | Yes | No | Clipboard |
| Papers | Yes | No | No | No | No | |
| Pybliographer | Yes | ? | No | Yes | No | No |
| refbase | Yes | Yes | Yes | Yes | Yes | Markdown, PDF, unAPI |
| RefDB | Yes | ? | Yes | Yes | No | DocBook, TEI |
| RefWorks | Yes | No | Yes | Yes | No | DOC, ODT |
| Zotero | Yes | Possible via plugin[27] | Yes | Possible via plugins[28] | Yes | Clipboard |
Word processor integration
Some reference management software include support for automatic embedding and (re)formatting of references in Word processor programs. This table lists this type of support for Microsoft Word, Pages, Apache OpenOffice / LibreOffice Writer, the LaTeX editors Kile and LyX, and Google Docs. Other programs are able to scan RTF or other textual formats for inserted placeholders which are subsequently formatted. Most reference management programs support copy/paste or drag-and-drop of references into any editor, but this is not meant here.
| Software | Word for Windows | Word for Mac | Word Online | Pages | Apache OpenOffice / LibreOffice | Kile/LyX | Google Docs | RTF scan[i] | Other |
|---|---|---|---|---|---|---|---|---|---|
| Bebop | No | No | No | No | No | No | No | No | None |
| BibBase | No | No | No | No | No | No | No | No | None |
| BibDesk | No | No | No | No | No | Yes | No | Yes | User-created scripts |
| BibSonomy | No | No | No | No | No | No | No | No | None |
| Bookends | Yes | Yes | No | Yes | Yes | No | No | Yes | Mellel, Nisus |
| Citavi | Yes | Yes | No | No | Only versions prior to 6.0 | Yes[29] | No | Only versions prior to 6.0 | LaTeX editors Texmaker, TeXnicCenter, TeXstudio, TeXworks, WinEdt, WinShell |
| EndNote | Yes | Yes | Yes[30] | Yes | No[31] | No | Yes[32] | Yes | No |
| JabRef | Yes[33] | ? | ? | ? | Yes[34] | Yes | No | ? | Emacs, Texmaker, TeXstudio, Vim, WinEdt |
| KBibTeX | No | ? | ? | ? | No | Yes | No | ? | None |
| Mendeley | Yes | Partial[j] | Yes[35] | No | Yes | No | No | ? | NeoOffice |
| Paperpile | Yes | Yes | No | No | No | No | Yes | No | No |
| Papers | Yes | Yes | Yes[36] | Yes[37] | Yes | No | Yes | No | Manuscripts app, Scrivener, Ulysses |
| Pybliographer | No | ? | ? | ? | Yes | Yes | No | ? | None |
| refbase | No | ? | ? | ? | Yes[38] | No | No | Yes | PIRA, MediaWiki, SPIP |
| RefDB | No | ? | ? | ? | No | No | No | No | None |
| RefWorks | Yes | Yes | No | No | No | No | Yes | Yes | None |
| Zotero | Yes | Yes | No | No | Yes | (with LyZ)[39] | Yes | Yes | Various[40] |
Database connectivity
This table lists the academic databases and search engines which reference managers can import from. In some cases, a search and retrieval can be conducted directly in the reference manager. In others, a bookmarklet or Firefox extension will allow a site to be scraped.
| Software | ArXiv | CiteSeer | IEEE Xplore | PubMed | Unpaywall[k] | Other |
|---|---|---|---|---|---|---|
| Bebop | No | No | No | No | No | No |
| BibBase | No | No | No | No | No | DBLP, Zotero, BibSonomy, Mendeley |
| BibDesk | Yes | Yes | No | Yes | No | ACM portal, Jstor, DBLP, Google Scholar, Web of Science, any Z39.50 or Entrez, and others |
| BibSonomy | Yes | Yes | Yes | Yes | No | Various[41] |
| Bookends | Yes | No | No | Yes | No | Web of Science, Amazon, Google Scholar, Z39.50 |
| Citavi | Yes | Yes | Yes | Yes | No | WorldCat/OCLC, Ovid, EBSCO, ProQuest, Web of Science, Z39.50 (4500+ online resources), SRU. Further catalogs are added upon request. Browser plugins (Firefox, Chrome, Internet Explorer) support DOI lookup, ISBN lookup, PubMed ID lookup, PMCID lookup, arXiv ID lookup, COinS and import from Wikipedia. |
| EndNote | Yes | No | Yes | Yes | No | Various,[42] any Z39.50 |
| JabRef | Yes | Yes | Yes | Yes | Yes[43] | ACM Portal, CrossRef, DBLP, DOAJ, DOI, GVK, Google Scholar, INSPIRE-HEP, Medline, MathSciNet, SAO/NASA Astrophysics Data System, Springer, and zbMATH |
| KBibTeX | Yes | Yes | Yes | Yes | No | BibSonomy, CiteBase, CSB, DBLP, Google Scholar, ScienceDirect, INSPIRE-HEP, Z MATH, Z39.50 |
| Mendeley | Yes | Yes | Yes | Yes | No | Various[44] |
| Paperpile | Yes | No | Yes | Yes | Yes | Google Scholar, INSPIRE-HEP, ACM portal, Jstor, Web of Science |
| Papers | Yes | No | Yes | Yes | No | Microsoft Academic, Google Scholar |
| Pybliographer | No | No | No | Yes | No | None |
| refbase | Yes | No | No | Yes | No | DOI lookup |
| RefDB | Yes | No | No | Yes | No | Any Z39.50 |
| RefWorks | No | No | No | Yes | No | Various |
| Zotero | Yes | Yes | Yes | Yes | Yes[45] | Various[46] |
Password "protection" and network versions
Some reference managers provide network functionality (N/A, not available, means the product has no networking, while "No" indicates it does but lacks an implemented feature). The Lightweight Directory Access Protocol (LDAP) is an open, vendor-neutral, industry standard application protocol for accessing and maintaining distributed directory services over an Internet Protocol (IP) network.[47]
| Software | Passworded | LDAP | Networking | |
|---|---|---|---|---|
| User-specific permissions[l] | Simultaneous write access | |||
| Bebop | No | ? | N/a | N/a |
| BibBase | N/a | ? | N/a | N/a |
| BibDesk | Yes | ? | No | No |
| BibSonomy | Yes | ? | Yes | Yes |
| Bookends | ? | ? | ? | ? |
| Citavi | Yes[m] | ? | Yes | Yes |
| EndNote | Yes | ? | No[n] | No[n] |
| JabRef | No | ? | No | Partial |
| KBibTeX | No | ? | N/a | N/a |
| Mendeley | Yes[o] | ? | Yes | Yes |
| Paperpile | Yes[p] | ? | Yes | Yes |
| Papers | Yes | ? | Yes | Yes[48] |
| Pybliographer | ? | ? | ? | ? |
| refbase | Yes | ? | Yes | Yes |
| RefDB | Yes | ? | Yes | Yes |
| RefWorks | Yes | ? | ? | Yes |
| Zotero | Yes[q] | ? | Yes | Yes |
Discontinued software
| Software | Developer | First public release | Latest stable release date | Latest stable version | Cost (USD) | Free software | License | Notes |
|---|---|---|---|---|---|---|---|---|
| Bebop | ALaRI Institute | 2007-11-08 | 2009-11-10 | 1.1 | Free | Yes | BSD | Web-based BibTeX front-end (Apache, PHP, MySQL) |
| Biblioscape | CG Information | 1997 | 2015-06-22 | 10.0.3.6 | US$79-299[a] | No | Proprietary | ODBC; web access in Pro ed; optional client/server; discontinued? |
| CiteULike | Oversity Limited | 2004-11 | Shut down on 2019-03-30[49] | Free | No | Proprietary[r] | Centrally hosted website | |
| colwiz | colwiz Ltd | 2011 | 2016-05-09 | Free / Online storage free up to 3 GB / Additional storage space available | No | Proprietary | Now combined with wizdom.ai | |
| Pybliographer | pybliographer developers | 1998-10-30 (0.2) | 2018-04-03 | 1.4.0 | Free | Yes | GNU GPL | Python/GTK2 |
| Qiqqa | Qiqqa | 2010-04 | 2020-10-04 | v80 | Free | Yes | GNU GPL | From end 2020, Open Source |
| Reference Manager | Thomson Reuters | 1984 | 2010 | 12.0.3 | Not for sale anymore, sales ceased December 31, 2015 | No | Proprietary | Network version; built-in web publishing tool; discontinued |
| Referencer | Referencer developers | 2008-03-15 | Discontinued | 1.2.2 | Free | Yes | GNU GPL | BibTeX front-end |
| RefME | RefME | 2014 | Shut down in 2017 | Free | No | Proprietary | Web, iOS and Android; Chrome and Safari Extensions available; discontinued | |
| SciRef | Scientific Programs | 2012 | 2020-07-30 | 1.6.2 | US$38.90 / Free trial version | No | Proprietary | |
| WizFolio | WizPatent | 2008-06 | Shut down in 2017 | Avatara | US$25 / Free Basic version | No | Proprietary | Centrally hosted website; discontinued |
Notes
- Price depends on affiliation (discounted price for students and members of academic, governmental, and nonprofit organizations), edition (Citavi for Windows for single users and teams with cloud storage, Citavi for DBServer for teams with intranet storage, Citavi Web with cloud storage), and, in the case of DBServer, on the license type (per seat license vs. concurrent license): "Products". www.citavi.com. Archived from the original on 2015-04-27.
- Supported through the bibutils plugin.
- Zotero can import references directly from the database after which this format is named, although it cannot read the format itself.
- Database can be exported as a whole in BibTeX format. Text (i.e. thoughts, comments, and quotations) can be fed into a number of TeX editors in LaTeX code or UTF-8.
- Database can be exported as a whole in BibTeX format.Insert citations via citation key generated by Mendeley.
- Can reformat references in a properly saved RTF document, allowing limited use in OpenOffice.org Writer, StarOffice, FrameMaker, Microsoft Works, WordPad, WordPerfect, Google Docs and others.
- Requires the Mendeley Reference Manager desktop app for Mac open to choose references.
- Includes all the other databases and open access repositories.
- Most databases allow one to create different user accounts to store records. Some further allow you to specify permissions (granting and denying some users the rights to edit or read some or all of your records). This column describes the latter.
- Storage in Citavi cloud or, with special license, in Microsoft SQL Server in intranet.
- via EndNote basic (cloud based)
- via Mendeley Web.
- Uses Google Account.
- via zotero.org.
- A developer kit is available. The community is invited to create plugins to access data off databases.