Perhaps you should try some spelling variations:
"estudios peruanos del." » "estudios urbanos del.", "estudios americanos del.", "estudios cervantinos del.", "estudios peruanos de.", "estudios peruano del.", "estudios peruano de."
"estudios ensayos serie." » "estudios etnicos serie.", "estudios ensayos sobre.", "estudios ensayos desde."
"estudios humanas serie." » "estudios mas serie.", "estudios humanidades serie."

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

• Performing a fuzzy search may retrieve terms with similar spellings: (((("estudios ensayos serie.") or ("estudios peruanos del."))) or ("estudios humanas serie."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("estudios ensayos serie.") OR ("estudios peruanos del."))) OR ("estudios humanas serie."))*.
• Removing quotes may allow a broader search: (((( estudios ensayos serie. ) or ( estudios peruanos del. ))) or ( estudios humanas serie. ))*.