Hi,

hope I understand right.

What you could try is the following :

Normally, you do have some chars (e.g. ) at the beginning of a
citation.
You could search the textlines for these characters (at the start of
each line) to differ between newer and elder text.

For example :

Hi, this is new text

and this is citation

and this is even older citation

Hope this will help you further

Klaus