How to group and reference with lookahead

In this example:

("Talking with Bengt Holmstrom 1" "#44")
("Chapter 1 What is Economics? 3" "#46")

, which is matched by regex ^(?!.*(Chapter|Part)).*\n\("Chapter.*\n, I would like to have two groups ("Talking with Bengt Holmstrom 1" "#44") and ("Chapter 1 What is Economics? 3" "#46").

To group, the above regex is modified to be^((?!.*(Chapter|Part)).*)\n(\("Chapter.*)\n. I want to refer to the two groups, but using \1 and \2 as their references as in \1\2 doesn't work. I was wondering if anything is wrong?

BTW, I am using gedit regex plugin.

Thanks!

Just refer to them as \1 and \3.

Just count the opening ( as you go from left to right. 1) is ((?!.*(Chapter|Part)).*), so the first line. 2) is (Chapter|Part) 3) is ("Chapter.*), so the second line starting with "Chapter.

Note that the ( that is the beginning of the lookahead is not counted.