Need help with undo for text editing

FROM : Magnus Strand
DATE : Mon Apr 04 10:37:55 2005

Hi,

I have made a Cocoa document based app.
I have 2 NSForm:s with text fields in the document window.

I need to add undo functionality for editing the text fields.
I would like to know if there is some specific info on the web about
implementing undo for text editing before I read the Apple docs.

Thanks in advance.

--
*Magnus Strand*