Perhaps you should try some spelling variations:
conferencia » convergencia, conference
referencias » references
magistrales." » magistrados.", mistrales."
mistrales." » muestrales.", minerales.", australes."
mitrales." » minerales.", litorales.", literales."
magistral." » mistral."

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

• Performing a fuzzy search may retrieve terms with similar spellings: "(conferencia or referencias) ((magistrales." or (mistrales." OR mitrales.")) or magistral.")~.
• If you are trying to use Boolean operators, they must be ALL CAPS: "(conferencia OR referencias) ((magistrales." or (mistrales." OR mitrales.")) or magistral.").
• The words AND, OR and NOT may confuse the search; try adding quotes: "\"(conferencia or referencias) ((magistrales.\" or (mistrales.\" OR mitrales.\")) or magistral.\")".
• Removing quotes may allow a broader search: (conferencia or referencias) ((magistrales. or (mistrales. OR mitrales. )) or magistral. ).
• Adding a wildcard symbol may retrieve word variants: "(conferencia or referencias) ((magistrales." or (mistrales." OR mitrales.")) or magistral.")*.