From Citizendium, the Citizens' Compendium
- Please sort and annotate in a user-friendly manner and consider archiving the URLs behind the links you provide. See also related web sources.
- Citizenship Laws of the World (pdf). United States Office of Personnel Management Investigations Service (March 2001). Archived from the original on 2006-04-04. Retrieved on 2007-03-07. “This LONG pdf file has a separate page about citizenship for EACH COUNTRY of the world -- takes 2 minutes to download”
- History of citizenship in the United States essay examining how citizenship changed from the 1640s to the present. Factors at work.