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