From Legalwriting.net which has better spacing than I’ve reproduced here:
“In Texas, we call it a court of appeals, not a court of appeal.
Thus the possessive becomes a problem. One commenter and others I have consulted prefer this form for a singular possessive:
the court of appeals’ opinionwhich looks better than–
the court of appeals’s opinion
but others always write around it–
the opinion of the court of appeals
By the way, if you are talking about two courts, it’s– the courts of appeals”