each month, i copy and paste the worksheet at the end of my workbook (we will
call it B) that was used for last months invoice. the worksheet contains
references to the sheet before it (call it A), so i have to rename those
references in the new sheet (call it C). i know there is an easier way to do
it...anyone know how?

this is my invoice setup:
Sheet C(links to B) Sheet B(link to A)
Sheet A(etc)
1.contract B, 5 A, 5
etc, 5
2.billed previous B, 4 A, 4
etc, 4
3.current amount manual manual
manual
4.billed to date 2+3 2+3
2+3
5.contract balance 1-4 1-4
1-4

thanks for any help.