Le Mourral, Trèbes (Aude): a fortified Languedocian late neolithic site reoccupied by Bell Beakers - Vaquer, Jean (Some new approaches to the Bell Beaker "phenomenon". Lost paradise ...? Proceedings of the 2nd Meeting of the "Association Archéologie et Gobelets", Feldberg (Germany), 18th-20th april 1997., 1998)