... and that way it works with the closed source (you will have to adjust strPath):
Code:
Sub Get_DataOfClosedWB()
Dim lngCol As Long
Dim lngMonth As Long
Dim lngStart As Long
Dim strformula As String
Const strPath As String = "H:\Excel-Forum-temp-MSEnglish\"
Const strCellRef As String = "$F$6"
With ActiveSheet
lngStart = .Cells(2, 1).Value
lngMonth = Month(.Cells(2, 1).Value)
Do While Month(lngStart + lngCol) = lngMonth
'Insert formula
.Cells(2, lngCol + 2).Formula = "='" & strPath & "[Source WKB.xlsx]" & Format(lngStart + lngCol, "DD.MM.YY") & "'!" & strCellRef
lngCol = lngCol + 1
Loop
End With
End Sub