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

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

• If you are trying to use Boolean operators, they must be ALL CAPS: (((("seis estudios peruanoss.") OR ("serie estudio urbanos."))) OR ("dos estudios urbanos."))~.
• Removing quotes may allow a broader search: (((( seis estudios peruanoss. ) or ( serie estudio urbanos. ))) or ( dos estudios urbanos. ))~.
• Adding a wildcard symbol may retrieve word variants: (((("seis estudios peruanoss.") or ("serie estudio urbanos."))) or ("dos estudios urbanos."))*.