http://www.eyewitnesstohistory.com/snpim.htm

http://www.eyewitnesstohistory.com/immigrating.htm 

https://history.state.gov/milestones/1921-1936/immigration-act 

https://www.learner.org/series/essential-lens-analyzing-photographs-across-the-curriculum/immigration-urbanization-and-identity-the-progressive-era-city/ 

https://picturethis.museumca.org/timeline/progressive-era-1890-1920s/immigration-period-restrictions/info