Perhaps you should try some spelling variations:
"pons estudios peruanoss." » "pons estudios peruanos.", "pons estudios urbanos.", "los estudios peruanoss.", "dios estudios peruanoss.", "seis estudios peruanoss."
"series estudio urbano." » "series estudios urbano.", "serie estudio urbano.", "serie estudios urbano.", "series estudios urbanos.", "series espacio urbano."
"dos estudios hispano." » "los estudios hispano."

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

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