Use of sheet reference in sumproduct formula

[PJV89]

Hi guys,
Hope you can help with the following.

In the Excel, numbered tabs have entity trial balances with month by month data in them, and I need the sum of the values for a particular month of particular ledger accounts. To designate the ledger accounts I have a column with x's in them if they need to be included in the calculation (will vary across entities).
My topsheet has rows with >100 entities and the same months and I now have the following formula to fetch the values for a month:
=SUMPRODUCT(('8a'!K278:K281="x")*('8a'!N278:N281))

I would like to replace the sheet reference '8a'! with a cell reference to be able to copy paste the formula down all the rows for easier processing. From what I have seen INDIRECT seems the way to go, but I've no idea how to get it to work with the rest of the formula.

Any suggestions for this?


Tabs have this format

Include	GL	Jan	Feb	Mar	Apr
	1000​	1​	2​	3​	4​
	1001​	4​	3​	3​	2​
x	1002​	1​	2​	4​	1​
x	1003​	2​	2​	2​	4​

Topsheet has this format and the formula in February should return 4, as the sum of accounts 1002 and 1003 because they have an x in front of them.

Entity name	Ref	Feb	Mar
Alpha	8a

 

[mart37]

=SUMPRODUCT((INDIRECT("'"&A1&"'!K278:K281")="x")*(INDIRECT("'"&A1&"'!N278:N281")))

 

[PJV89]

Brilliant, that works. Thanks a lot!