Sorting is available for most results lists, though the sort options may vary per collection, and all sorting is conditional to the maximum sort threshold allowed by the system. In the upper right hand corner of the results by item display you will see either a menu of sort options, or a message indicating that the threshold has been exceeded. If you see that the threshold has been exceeded, try using the "revise this search" link to add more terms to the search in hopes of retrieving a smaller result.

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Fig 1: The sort options menu showing a) normal sorting options; and b) when sort threshold has been exceeded ;