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

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

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