I asked about a formula and I have one more question.

I have composed the following formula
=SUMPRODUCT(--('Wpg #s data'!C6:C500="One"),--('Wpg #s
data'!J6:J500DATE(2004,12,1)))

But instead of specifying a date, I want to use a cell reference. I I had
the cell of J4 as the date to use, how would the formula look?