Perhaps you should try some spelling variations:
la literatura » la litterature, a literature
case studien » case studie, case studieson, cases studies
case studies » case study
e filosofica » e filosofiche, a filosofia, y filosofia
e filosofia » la filosofia

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: sets ((case studien) OR (case studies)) ((e filosofica) OR (e filosofia)) la literatura.
• The words AND, OR and NOT may confuse the search; try adding quotes: "sets ((case studien) OR (case studies)) ((e filosofica) or (e filosofia)) la literatura".
• Adding a wildcard symbol may retrieve word variants: sets ((case studien) OR (case studies)) ((e filosofica) or (e filosofia)) la literatura*.