Function CLSC(Dates As Date) As Integer
Dim Semaine As Integer
Semaine = Int((Dates - DateSerial(Year(Dates), 1, 1) + _
((Weekday(DateSerial(Year(Dates), 1, 1)) + 1) _
Mod 7) - 3) / 7) + 1
If Semaine = 0 Then
Semaine = CLSC(DateSerial(Year(Dates) - 1, 12, 31))
ElseIf Semaine = 53 And (Weekday(DateSerial(Year(Dates), 12, 31)) - 1) _
Mod 7 <= 3 Then
Semaine = 53
End If
CLSC = Semaine
End Function