Perhaps you should try some spelling variations:
"seis estudios cervantinos." » "seis estudios mercantiles.", "seis estudios criticos.", "seis estudios andinos.", "los estudios cervantinos.", "dos estudios cervantinos.", "dios estudios cervantinos."
"series estudioss urbano." » "series estudios urbano.", "serie estudios urbano.", "serie estudio urbano.", "series estudio urbano."
"tres estudios urbanos." » "otros estudios urbanos.", "los estudios urbanos.", "dos 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 estudioss urbano.") or ((("tres estudios urbanos.") or ("seis estudios cervantinos."))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("series estudioss urbano.") OR ((("tres estudios urbanos.") OR ("seis estudios cervantinos."))))*.
• Removing quotes may allow a broader search: (( series estudioss urbano. ) or ((( tres estudios urbanos. ) or ( seis estudios cervantinos. ))))*.