Rivers of Steel National Heritage Area:

http://www.riversofsteel.com/

Pennsylvania Museum and History Commission Biography of Governor Robert Pattison:

http://www.phmc.state.pa.us/portal/communities/governors/1876-1951/robert-pattison.html

Battle of Homestead Foundation:

http://www.battleofhomesteadfoundation.org/

University of Pittsburgh's "Pittsburgh and Western Pennsylvania Labor Legacy” site:

http://www.library.pitt.edu/labor_legacy/

The Labor Legacy site includes links to documents on this page:

http://www.library.pitt.edu/labor_legacy/homestead.htm

Pennsylvania Labor History Society:

http://palaborhistory.org/index.php

An outline of PA's labor history as compiled by the Pennsylvania Center for the Study of Labor Relations:

http://libs0400.acadlib.iup.edu/depts/speccol/articles/An%20Outline%20of%20Pennsylvania%20Labor%20History%201780-2000.pdf

ExplorePAhistory.com's History of Labor in Pennsylvania from the site's "Stories From PA History" series:

http://explorepahistory.com/story.php?storyId=1-9-22

Historical Society of Western Pennsylvania:

http://www.heinzhistorycenter.org/historyCenter.aspx

List of PA state historical markers commemorating Pennsylvania's labor history:

http://www.laborhistorylinks.org/PDF%20Files/cb59decf126b43dcbe40a5b21968f7143-2.pdf

A timeline of labor history created by the AFL-CIO:

http://www.aflcio.org/About/Our-History/Labor-History-Timeline

Penn State University Library's Historical Collections and Labor Archives:

http://guides.libraries.psu.edu/SCL/labor

American Labor Museum:

http://www.labormuseum.net/

Youngstown Historical Center of Industry and Labor:

http://www.ohiohistory.org/museums-and-historic-sites/museum--historic-sites-by-name/youngstown

Labor and Industry Museum:

http://www.laborandindustrymuseum.org/