Use the public-domain citation form

Error²Federal courts, Illinois courts21st and 22nd editions

A public-domain citation is the year, the court token, the district in parentheses for the Appellate Court, and the number — “2012 IL App (1st) 100123”.¹

1. 1Ill. S. Ct. R. 6 Commentary (May 31, 2011); M.R. No. 10343(A); R. 10.3.3 Public Domain Format; T1.3 States and the District of Columbia.
2. 2An error: the rule in note 1 allows one form, and this is not it.