Perhaps you should try some spelling variations:
"serie estudios peruanos." » "serie estudios urbanos.", "serie estudios americanos.", "serie estudios ensayos."
"series estudios hispanic." » "series estudios hispanicos.", "series estudios hispano.", "series studies hispanic.", "seis estudios hispanic.", "tres estudios hispanic.", "leyes estudios hispanic."
"serie estudios urbano." » "serie estudios urbanos.", "serie estudio urbano.", "serie estudios hispano."

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: (((("serie estudios urbano.") OR ("serie estudios peruanos."))) OR ("series estudios hispanic."))~.
• Removing quotes may allow a broader search: (((( serie estudios urbano. ) or ( serie estudios peruanos. ))) or ( series estudios hispanic. ))~.
• Adding a wildcard symbol may retrieve word variants: (((("serie estudios urbano.") or ("serie estudios peruanos."))) or ("series estudios hispanic."))*.