"Civilization's Next Step" (HC.MC.975.07.105), Quaker & Special Collections, Haverford College, Haverford, PA.
"Civilization's Next Step" (HC.MC.975.07.105), Quaker & Special Collections, Haverford College, Haverford, PA. https://archives.tricolib.brynmawr.edu//repositories/5/resources/1011 Accessed May 20, 2024.
