Citing 'several' studies in one statement... cite all of them or use 'for example'?
If you doubt that a study should be included in the bibliography, then probably you don't consider it worth citing. Make a selection and then include every one of them in the bibliography. In the body you could say something like, "An exhaustive body of empirical studies exists on this topic [see: Study 1, Study 2,... Study N]. In particular, [Study X, Study Y] are most relevant to our work...".

Not including cited work in bibliography will be considered at best a sign of laziness and at worst an indication of unethical behaviour.