Use parentheses for the notation

Warning²Federal courts, Illinois courts21st and 22nd editions

A note of added emphasis, of an alteration or of dropped citations sits in parentheses after the citation; brackets inside a quotation mark words the writer changed or supplied.¹

1. 1R. 5.2(d)(i) Changes to citations. Tables: B5.3 Modifying Quotations and Citations for Clarity; R. 5.2(a) Substitution of letters or words.
2. 2A warning: the form is usually wrong under the rule in note 1, and context can justify it.