Plugin adding a specific field in the wysiwyg

Hi,

I’m developing a website where editors write articles. They need also to show the sources, for each paragraph. The goal is that they get in the wysiwyg editor a button that adds a paragraph with special styling I could style in the CSS (I want it to be a expand/collapse, may be I can customize that)

I wanted to know if there is such a plugin or something close I could use.

Thanks =D