Madarasz, Anne (1998). "Chapter 2: Beginnings". Glass: Shattering Notions(PDF). Pittsburgh, PA: The Historical Society of Western Pennsylvania. pp. 18–19. Archived from the original(PDF) on 13 September 2011. Retrieved 17 July 2014.
Madarasz, Anne (1998). "Chapter 2: Beginnings". Glass: Shattering Notions(PDF). Pittsburgh, PA: The Historical Society of Western Pennsylvania. pp. 18–19. Archived from the original(PDF) on 13 September 2011. Retrieved 17 July 2014.