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I was browsing the chessopedia and found there was no entry for zwischenzug. I was going to create an entry, but I could not find how.
In the box on the upper right Create a wiki article. Should be a link to "Submit a new wiki article".
Go to the main chessopedia page (http://www.chess.com/chessopedia) and, in the top right corner (under the "My Home" button) there is a box that says: Submit a new wiki article. Actually, I think you can just click on the last link I gave you.