I have a spreadsheet that has 3 columns. I need to be able to make what I
call a compound reference. It's really hard to explain but I need to do the
following:

='Sheet A'!X(b1)

whe
The current sheet is Sheet B
Sheet A is the sheet containing the cell needed
X(b1) refers to column X of sheet A and
the (b1) refers to the cell in sheet B that contains the row number to use
in sheet A for row X

Thanks in advance for your help!