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

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

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