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