Search Wikipedia through Opera

One of the simplest but lovliest inventions by the Opera browser is to search google through writing "g" in the address bar like so:
    g selfelected

It is easy to extend this to search Wikipedia through for instance "w".
Meny:Tools->Preferences->Search->Add->Details
    key: w    <- e.g.     address: http://en.wikipedia.org/wiki/Special:Search?search=%s

To let Google search wikipedia.

    key: gw    <- e.g.     address: http://www.google.com/search?q=site:wikipedia.org+%s

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