Perhaps you should try some spelling variations:
"series estudios peruanos." » "series estudios americanos.", "series estudios ensayos.", "series estudios cervantinos.", "serie estudios peruanos.", "seis estudios peruanos.", "leyes estudios peruanos."
"tres estudios hispano." » "otros estudios hispano.", "los estudios hispano.", "dios estudios hispano.", "tres estudios hispana.", "tres estudios hispanic."
"dos estudios urbanos." » "los 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 peruanos.") or ("dos estudios urbanos."))) or ("tres estudios hispano."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("series estudios peruanos.") OR ("dos estudios urbanos."))) OR ("tres estudios hispano."))*.
• Removing quotes may allow a broader search: (((( series estudios peruanos. ) or ( dos estudios urbanos. ))) or ( tres estudios hispano. ))*.