The European Large-Area Infrared Space Observatory Survey V: a BeppoSax hard X-ray survey of the S1 region by Alexander, D, La Franca, F, Fiore, F, Barcons, X, Ciliegi, P, Danese, L, Della Ceca, R, Franceschini, A, Gruppioni, C, Matt, G, Matute, I, Oliver, S, Pompilio, F, Wolter, A, Efstathiou, A, Heraudeau, P, Perola, G, Perri, M, Rigopoulou, D, Rowan-Robinson, M, Serjeant, S