http://www.pbs.org/opb/historydetectives/feature/the-early-labor-movement/
https://www.history.com/topics/labor
https://whorulesamerica.ucsc.edu/power/history_of_labor_unions.html
https://www.npr.org/templates/story/story.php?storyId=5758863
https://www.history.com/topics/labor
https://www.hawaii.edu/uhwo/clear/home/Timeline-US.html
http://www.yourarticlelibrary.com/trade-unions/history-of-trade-union-movements-in-india/32988
https://www.marxists.org/history/international/comintern/sections/britain/periodicals/communist_review/1922/05/indian_labour_mvt.htm
http://www.esocialsciences.org/eSS_essay/Employment/Labour%20%20Movements%20in%20India_Manjusha%20Nair.pdf