Public Function FilterZiffer(ByVal strText as String, ByVal Ziffer As Integer) _
  As String
		Dim strZiffer As String = ""
 
		For i As Integer = 0 To strText.Length-1
			If strText.Chars(i) = CStr(Ziffer) Then
				strZiffer += strText.Chars(i)
			End If
		Next
 
		If strZiffer.Length >= 9 Then
			Return Ziffer
		Else
			Return Nothing
		End If
	End Function