Here is an example.
'=SUMPRODUCT((MONTH('C:\yourfolderl\[yourfile.xls]CHECKS'!$A$7:$A$1000)=MONT
H(A119))*(LEFT('C:\yourfolderl\[yourfile.xls]CHECKS'!$C$7:$C$1000,4)="10yr")
*'C:\yourfolderl\[yourfile.xls]CHECKS'!$D$7:$D$1000)

--
Don Guillett
SalesAid Software

"levie" wrote in message
...
Most of the time I'm building workbooks with formulas referencing to other
workbooks, in order that I have the accurate values, all workbooks linked
should be open at the same time, is this how it really works? is there a
better way of doing this; that is, an option of not opening the other
files.