Remove the closing period

Warning²Federal courts, Illinois courts21st and 22nd editions

An explanatory parenthetical is not a sentence of its own; the citation it follows supplies the period, unless the parenthetical quotes text that reads as a full sentence.¹

1. 1B1.3 Explanatory Parentheticals. Tables: R. 1.5(a)(i) Phrases not quoting the authority; R. 1.5(a)(ii) Phrases quoting the authority.
2. 2A warning: the form is usually wrong under the rule in note 1, and context can justify it.