Use the standard month abbreviation

Error²Federal courts, Illinois courts21st and 22nd editions

Table T12 abbreviates months as Jan., Feb., Mar., Apr., Aug., Oct., Nov., and Dec. May, June, and July are never abbreviated. September is “Sept.” in the 21st edition and “Sep.” in the 22nd.¹

1. 1T12 Months; B16.1.4 Newspaper Articles.
2. 2An error: the rule in note 1 allows one form, and this is not it.