POLOS DE REGGE REGGE POLES DISPERSION RELATIONS EQUATIONS GAUGE INVARIANCE INVARIANZA DE UN PATRON LOW ENERGY MEAN-FIELD THEORY MODELO DE VENECIANO SINGULARITY TEORIA DEL CAMPO MEDIO VENEZIANO MODEL AMPLITUDES DE DISPERSION ASYMPTOTIC CONDITIONS Application of a modified mean-field method to a gauge-invariant variational calculation CONDICIONES ASINTOTICAS CROSS SECTIONS DUALITY Finite energy sum rules with ... veneziano amplitudes Finite energy swa rules vith ...veneziano amplitudes HIGH-ENERGY LIMIT Indications on the g-Like Singularities in the Complex J-Plane LIMITE DE ALTA-ENERGIA MODELO VENEZIANO MOMANDELSTAM REPRESENTATION Nonvanishing Asym ptotic Total π N Cross-Sections from Continuous M oment Sum Rules REGLAS DE SUMA REPRESENTACION DE MANDELSTAM SCATTERING AMPLITUDES SECCIONES EFICACES