Mo. Rev. Stat. § 67.820: Notice, how sent, by whom.

1. The county clerk, circuit clerk, city clerk, or clerk of any political subdivision, upon whom the duty is imposed by law to publish notice required by law in regard to the formation of a special taxing district for public works or public improvements, shall mail by certified mail with return receipt a copy of each published notice in regard to the formation of any special taxing district within the county, city or other political subdivision to each nonresident property owner who has requested such notice by affidavit as provided in section 67.810.

2. The county clerk, circuit clerk, city clerk, or clerk of any political subdivision, upon whom the duty is imposed by law to publish notice required by law in regard to any special assessment by a special taxing district, shall mail by certified mail with return receipt a copy of each published notice to each nonresident property owner who has requested such notice by affidavit as provided in section 67.810.