Use the matching series letter

Error²Federal courts, Illinois courts21st and 22nd editions

The Inter-American Court publishes its rulings in lettered series, matched to the kind of decision: an advisory opinion belongs in one series, a judgment between named parties in another.¹

1. 1R. 21.5.5(a) Advisory Opinions; R. 21.5.5(b) Contentious Cases; R. 21.5.5 Inter-American Court of Human Rights. Tables: T3.7 Inter-American Court of Human Rights.
2. 2An error: the rule in note 1 allows one form, and this is not it.