Abbreviate the possessive case name

Warning²Federal courts, Illinois courts21st and 22nd editions

Case names in citations use the T6 abbreviations, and a plural possessive keeps its apostrophe on the abbreviated word, so “Employees’” becomes “Emps.’”.¹

1. 1T6 Case Names and Institutional Authors in Citations. Tables: R. 10.2.2 Additional Rules for Case Names in Citations.
2. 2A warning: the form is usually wrong under the rule in note 1, and context can justify it.