olemus
liik isikukoode (USAs jm), 9-kohaline numberkood, eelkõige maksustuse otstarbeks
= type of personal identification number (in the USA, etc.), a 9-digit number code, primarily for tax purposes

ülevaateid
https://en.wikipedia.org/wiki/Social_Security_number

https://www.ssa.gov/history/ssn/geocard.html

http://www.lavasurfer.com/info/socialsecurity.html

https://www.ssa.gov/policy/docs/ssb/v69n2/v69n2p55.html

https://www.barcodesinc.com/articles/structure-of-social-security-numbers.htm