Perhaps you should try some spelling variations:
"sus retos, 12 meses." » "los retos, 12 meses." (Expand Search), "sus retos, 11 meses." (Expand Search), "sus retos, 36 meses." (Expand Search), "sus retos, 6 meses." (Expand Search)
"ii retos, 12 meses." » "dir retos, 12 meses." (Expand Search), "xxi retos, 12 meses." (Expand Search), "y retos, 12 meses." (Expand Search), "ii retos, 11 meses." (Expand Search), "ii retos, 36 meses." (Expand Search), "ii retos, 6 meses." (Expand Search)
"os retos, 12 meses." » "os retos, 11 meses." (Expand Search), "os retos, 36 meses." (Expand Search), "os retos, 6 meses." (Expand Search), "los retos, 12 meses." (Expand Search), "odm retos, 12 meses." (Expand Search), "y retos, 12 meses." (Expand Search)

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• Performing a fuzzy search may retrieve terms with similar spellings: (("ii retos, 12 meses.") OR ((("os retos, 12 meses.") OR ("sus retos, 12 meses."))))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"ii retos, 12 meses.\") OR (((\"os retos, 12 meses.\") OR (\"sus retos, 12 meses.\"))))".
• Removing quotes may allow a broader search: (( ii retos, 12 meses. ) OR ((( os retos, 12 meses. ) OR ( sus retos, 12 meses. )))).
• Adding a wildcard symbol may retrieve word variants: (("ii retos, 12 meses.") OR ((("os retos, 12 meses.") OR ("sus retos, 12 meses."))))*.