Sum Multiple Criteria
 

I've been reading some of the postings and trying to create a formula that
adds from one column based on multiple criteria:

=SUMPRODUCT(--('BOM LIST'!$J$8:$J$770=B31),--('BOM
LIST'!$A$8:$A$770={"S","S-FED","O"}),--('BOM
LIST'!$G$8:$G$770={"F","Q","R"}),'BOM LIST'!$Z$8:$Z$770)

What am I doing wrong?

Also, can anyone reccommend a book on how to increase my knowledge of such
formulas?