Row 1 contains labels / headings:

A B C
Sheet 1 Sheet 2 Sheet 3, etc.

In row 2, part of the formula will look to a cell on the worksheet that
corresponds to the heading. For example, "='Sheet 1'!A3+'Sheet 1'!A5"

I'd like to "insert" the reference to the worksheet by referencing the cell
in row 1. I think there must be an easy way to do it, and it would save me a
lot of time.

Thanks in advance!