Can someone assist. Although the formula is not rejected it doesn't do anything. In the formula below l3:af3 refer to a range of consecutive dates. o30 to a date about midway in the range between l3 and af3, and l20:af50 to a range of general numbers. What am I doing wrong??????????
As you can see I am working across two worksheets.

=SUMIF(book2!L3:AF3, "=book1!O30", book2!L20:AF20)