Let's assume that 10 empirical studies have been done for topic x. If I want to mention the following: Several studies have been conducted to deal with topic x (study 1; study 2; study 3).
My question: when I mention the word 'several', am I obligated to cite ALL the 10 empirical studies in the citation? Can I just cite a few? Should I use 'for example' to tell the reader that I am citing only 3 related studies, however others studies do exist?
Assuming the empirical studies with topic X involves the application of various methods associated with X, aspect of citing the number of available examples depends on your motive.
If you are illustrating a method, then citing only a few like two or three would be fine. This can be when you wish to show the applicability (or inapplicability) of a method Y for the topic X citing only few of the papers that uses Y on X.
On the other hand, if you wish to do a detailed study on different methods applied in different ways on topic X, then you would have to cite all the available empirical studies done on X. Note that you would also have to give an account on each of the material you have cited. This would be the obvious case for a proper survey.
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.
