Reference retrieval can be even easier if you use of one these extensions:
This extension adds a button that opens a mini-search window.
This extension adds a Firefox toolbar.
This adds a toolbar to your browser as well as adds a right-click menu option for reference resolving.
Development of this extension ceased in mid-2012 when Apple decided not to publish Safari 6.0 for Windows. Stable work is not guaranteed.
Developed by Dave Flanagan.
This program will resolve any selected text as a reference after you click Win+C. Tested on Windows XP. The archive contains an .EXE file that can be added to your startup list as well as an editable AutoHotKey file (requires AutoHotKey software).
This extension adds the ability to quickly resolve references on Macs using a keystroke combination. To download, click the image below. For source code and explations, see Chris Swain's original post.
This is customizable HTML code that adds a tiny Resolver widget on your webpage. Please read the included readme.txt
Firefox users can set up Reference Resolver as the default search engine (used both in the search field and the address bar). To do that, go to the main Resolver page and click the small triangle near the search field, as shown below. You can always switch back to your original search engine from that menu.