Using indirect to sum multiple worksheet cells

Hi,
This works:
=SUM(INDIRECT("'Sheet2'!$C$1:$C$5"),INDIRECT("'Sheet3'!$C$1:$C$5"))

These do not:
=SUM(INDIRECT({"'Sheet2'!$C$1:$C$5";"'Sheet3'!$C$1:$C$5"}))
=SUM(INDIRECT("'"&Sheets&"'!$C$1:$C$5"))
Where Sheets refers to =Sheet1!$A$1:$A$2
[A1=]Sheet1, [A2=]Sheet2

For the last two ONLY Sheet2 is summed, not sheet3

Any suggestions?

Yes, you are right, the last 2 can not work
Because the ref_txt is neither a cell nor a range

Thank you for the reply. I may have oversimplified my question. I want to be flexible and therefore I would like to use dynamic names in the future.

I found something similar in the forum:
=SUMPRODUCT((COUNTIF(INDIRECT("'"&sheets&"'!$C$1:$C$15"),D$2&$A7)))
Where sheets again is a range of cells containing Sheetnames.

How can I use names in my indirect?

I could get it to work using SUMPRODUCT/SUMIF:

=SUMPRODUCT(SUMIF(INDIRECT({"Sheet1!A1:A5","Sheet2!A1:A5"}),"<>"))

Richard

Dear Richard,

I rebuilt it a bit and ... it works.
=SUMPRODUCT(SUMIF(INDIRECT("'"&Sheets&"'!$C$1:$C$15"),"<>"))

Gr,
Ricardo