Function S(v)
Application.Volatile
Dim colref%, fn$, col%, w As Worksheet, lig As Variant
colref = 3 'colonne C
With Application.Caller
fn = .Parent.Name
col = .Column
End With
For Each w In Worksheets
If w.Name <> fn Then
lig = Application.Match(v, w.Columns(colref), 0)
If IsNumeric(lig) Then S = S + Val(w.Cells(lig, col))
End If
Next
End Function