In the infobox template for a region, inserting a ref in this variable:
|area_rank = 212th<ref>Including [[Rose Atoll]] and [[Swains Island]]</ref>|
Generates this preview output in the infobox:
With 212th linked as expected, and the UNIQ...QINU string linked to "#cite_note-1" as expected. Tested on w:en:American_Samoa.