From Opus

In order to contribute, you must be in a position to post your material, which means that either:

• you own the copyright to the material, for instance because you produced it yourself, or
• you acquired the material from a source that allows the licensing under GFDL, for instance because the material is in the public domain or is itself published under GFDL.

[edit] If you are the owner of content being used without your permission

If you are the owner of content that is being used on the Opus without your permission, then you may request the page be immediately removed by using the contact us link at the bottom of every page. You may also blank the page and replace it work the words {{copyvio|URL or place you published the text}} but the text will still be in the page history). Either way, we will, of course, need some evidence to support your claim of ownership.