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.", "tres estudios peruanos."
"reales estudios urbanos." » "reales estudio urbanos.", "rurales estudios urbanos.", "locales estudios urbanos."
"series espacio urbano." » "series spain urbano.", "versus espacio urbano.", "sociales espacio urbano.", "series espacio urbanismo."

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

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