Mo. Rev. Stat. § 509.030
Every pleading of a party represented by an attorney shall be attributed to at least one attorney of record in his individual name, whose address shall be stated. A party who is not represented by an attorney shall affix his name to his pleading and state his address. Except when otherwise specifically provided by rule or statute, pleadings need not be verified or accompanied by affidavit. Pleadings shall be attributed to a party or attorney or signed in the manner provided by supreme court rule. Any statutory requirement that pleadings be signed by any person shall be satisfied by compliance with such rules. Any statutory requirement that pleadings be acknowledged under oath, verified or notarized may be satisfied by a declaration that the pleading is made under penalty of perjury.
§ 509.030, RSMo