Examples of interlopers that could affect our LBGs selection. We show the galaxy spectra and the position of our three filters over it. Top left panel: the spectra of an elliptical galaxy at z = 0.45, with a strong Balmer break located at ﹩{\lambda }_{\mathrm{obs}}=5840﹩ Å and intense calcium H and K absorption. Top right panel: the spectra of a galaxy at z = 0.60, with intense O II emission line at ﹩{\lambda }_{\mathrm{obs}}=5925﹩ Å. Bottom left panel: the spectra of a galaxy at z = 1.04, with Mg I and Mg II absorption at ﹩{\lambda }_{\mathrm{obs}}\sim 5650﹩ Å. Bottom right panel: the spectra of a galaxy at z = 1.23, with a large break at ﹩{\lambda }_{\mathrm{obs}}=5887﹩ Å.