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

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

• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"series estudios peruanoss.\") OR (\"dos estudios urbanos.\"))) OR (\"tres estudios urbano.\"))~".
• Removing quotes may allow a broader search: (((( series estudios peruanoss. ) OR ( dos estudios urbanos. ))) OR ( tres estudios urbano. ))~.
• Adding a wildcard symbol may retrieve word variants: (((("series estudios peruanoss.") OR ("dos estudios urbanos."))) OR ("tres estudios urbano."))*.