System preferences authorities.pref#UNIMARCAuthorityField100# Use the following text for the contents of UNIMARC authority field 100 position 08-35 (fixed length data elements). Do NOT include the date (position 00-07): UNIMARC authority field 100 position 08-23 https://cdn.ifla.org/wp-content/uploads/2019/05/assets/uca/unimarc-authorities-format.pdf