Why are the 856 URL links not displaying in Discovery?

In a Marc Record the 856 Tag for the URL will display in Discovery, only if set rules are adhered to.

856 MARC tags must have the 1st indicator set to 4 and 2nd indicators set to either 0, 1 or 2 - it cannot be left blank
Most commonly, you will see the 1st indicator with 4 (the HTTP (Hypertext Transfer Protocol) and the 2nd indicator with 0 (resource))
There are rules applied to Links from a Master WorldCat record 856 and 956 to open access content/free content in Discovery, that need to be adhered to
WorldCat Discovery uses WorldCat MARC indicators 4 & 0 to inform the availability link displayed
Then WorldCat MARC indicator 4 & 1 or 4 & 2 are used to inform description displays
An example of a display rule within Discovery would be that an 856 tag where the $u field contains .gov/ and .pdf OR $u field contains .edu AND .pdf will display in Discovery
However, the 856 tag will not display in Discovery if the $u field contains loc.gov AND the 1st indicator is set to 4 AND 2nd indicator is set to 0, 1, or 2.

This example will display, as it has both .gov and .pdf in the URL:

856| 4| $u http://www.tpk.govt.nz/_documents/TKOM_MTS _report_english.pdf

This example will not display, as there is no .pdf in the URL:

856 |4 | ǂu http://ndhadeliver.natlib.govt.nz/content-aggregator/getIEs?system=ilsdb&id=1336112 ǂx NDHA Access Right = 100

See Full Text and Open Access Links for further information on the rules that define what 856 tags will display in Discovery.

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