Function SummeWennAb(Bereich As Range, Suchkriterien, Summe_Bereich As Range)
Dim l As Long, u As Long, i As Long, s As Double, Mappe As Workbook
Application.Volatile
Set Mappe = Bereich.Parent.Parent
l = Bereich.Parent.Index: u = Summe_Bereich.Parent.Index
If l > u Then i = u: u = l: l = i
If l = u Then u = Mappe.Sheets.Count
If Mappe.Name <> Summe_Bereich.Parent.Parent.Name Then SummeWennAb = "#Mappe!": Exit Function
For i = l To u
s = s + Application.WorksheetFunction.SumIf(Mappe.Sheets(i).Range(Bereich.Address), _
Suchkriterien, Mappe.Sheets(i).Range(Summe_Bereich.Address))
Next i
SummeWennAb = s
End Function