The Wayback Machine - https://web.archive.org/web/20190603155600/https://pe.usps.com/text/pub28/28apd_001.htm

Appendix D

Unusual Addressing Situations

There are a number of addressing situations that can create matching and standardization difficulties. The standards contained in this document do not account for every type of addressing situation that may occur; however, these standards are comprehensive and reflect a majority of address styles.

There are some addressing situations of which a mailer should be aware. These include: