Archives and Primary Sources
And the second is the finding aid for the Helen Clay Frick Papers in New York:
Much of the primary source material from the Helen Clay Frick Papers I have shared throughout this book, as well as digitized publications in Documenting Pitt. Those materials were found with help from archivists and also through manual searching on my part. The newspaper articles, such as the one from the Pittsburgh Post Gazette, were searched for using the Google News Archive.