Rule 28(k) of the Mississippi Rules of Appellate Procedure provides that:
"(k) Citation of Supplemental Authorities. When pertinent and significant
authorities come to the attention of counsel after the party's brief has been filed, or after oralargument or decision, the party may promptly advise the clerk of the Supreme Court, by
letter with a copy to all counsel, setting forth the citations. There shall be a reference either
to the page of the brief or to a point argued orally to which the citations pertain, but the letter
shall, without argument, state the reasons for the supplemental citations. Any response shall
be made promptly and shall be similarly limited."
The way this is typically done is to simply write a letter to the court clerk advising them of the new case, stating what are of the brief including page numbers in your brief that it applies to, and the reason for the supplemental citation. To me the confusing part of this is where it says to state the reasons for the supplemental citation but without argument. The best educated guess I have on how to interpret this is to simply state why the case is relevant for a particular issue without any detailed analysis regarding the particular facts of your case. In Huseth, the Appellate had a supplemental brief struck because leave of court was not obtained. The Appellee had filed a motion to strike it but then filed a 28(k) letter to make the court aware of the same case.