https://papersofprinceton.princeton.edu/princetonperiodicals/?a=d&d=princetonpress18591223.1.3&srpos=3&e=-------en-20--1-byDA-txt-txIN-%22western+union%22------ 
https://papersofprinceton.princeton.edu/princetonperiodicals/?a=d&d=princetonpress18581015.1.1&srpos=1&e=-------en-20--1-byDA-txt-txIN-%22western+union%22------ 
http://papersofprinceton.princeton.edu/princetonperiodicals/?a=d&d=princetonpress18590916.1.1&srpos=2&e=-------en-20--1-byDA-txt-txIN-%22western+union%22------ 
https://www.nps.gov/articles/000/russamertelegraph.htm 
https://ethw.org/Milestones:Transcontinental_Telegraph,_1861 
https://www.history.com/articles/abraham-lincoln-telegraph-civil-war 
https://thebhc.org/telegraph-act-1866-entering-wedge-against-western-union-monopoly 
https://www.stocktickercompany.com/wp-content/uploads/2016/10/StockTickerBrochure.pdf 
https://papersofprinceton.princeton.edu/princetonperiodicals/?a=d&d=princetonstandard18690423.2.4&srpos=5&e=-------en-20--1-byDA-txt-txIN-%22western+union%22------ 
https://papersofprinceton.princeton.edu/princetonperiodicals/?a=d&d=princetonpress18731115.1.2&e=------187-en-20--1-byDA-txt-txIN-%22western+union%22+%22money%22------ 
https://cdnc.ucr.edu/?a=d&d=SDU18830720.2.14&e=-------en--20--1--txt-txIN-------- 
Western Union and the creation of the American corporate order: Chapter 8
https://cdnc.ucr.edu/?a=d&d=SDU18830720.2.14&e=-------en--20--1--txt-txIN--------