ACUERDO DE RÉGIMEN DE CO-TUTELA DE UNA TESIS DOCTORAL ENTRE LA UNIVERSIDADE DE VIGO (ESPAÑA) Y LA UNIVERSIDAD DE CARTAGO (TÚNEZ) Y AN / CO-OPERATION AGREEMENT FOR THE JOINT SUPERVISION OF A DOCTORAL THESIS BETWEEN THE UNIVERIDADE DE VIGO (SPAIN) AND THE UNIVERSITY OF CARTHAGE (TUNIS) AND AN