Perhaps you should try some spelling variations:
"los estudios peruanos." » "los estudios americanos.", "los estudios ensayos.", "los estudios cervantinos."
"tres d'estudis urbans." » "tres estudio urbano.", "tres estudios urbano.", "tres estudios urbans."
"series estudios urbanos." » "serie estudios urbanos.", "seis estudios urbanos.", "tres estudios urbanos."

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("series estudios urbanos.") or ((("tres d'estudis urbans.") or ("los estudios peruanos."))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("series estudios urbanos.") OR ((("tres d'estudis urbans.") OR ("los estudios peruanos."))))*.
• Removing quotes may allow a broader search: (( series estudios urbanos. ) or ((( tres d'estudis urbans. ) or ( los estudios peruanos. ))))*.