Roy F. Nichols: The Library, The Mystery of the Dallas Papers. In: Pennsylvania Magazine of History and Biography. Band73, Nr.3. The Historical Society of Pennsylvania, Philadelphia Juli 1949, S.349–392, hier S. 352 (psu.edu).
Roy F. Nichols: The Library, The Mystery of the Dallas Papers. In: Pennsylvania Magazine of History and Biography. Band73, Nr.3. The Historical Society of Pennsylvania, Philadelphia Juli 1949, S.349–392, hier S. 353–354 (psu.edu).
Roy F. Nichols: The Library, The Mystery of the Dallas Papers. In: Pennsylvania Magazine of History and Biography. Band73, Nr.3. The Historical Society of Pennsylvania, Philadelphia Juli 1949, S.349–392, hier S. 349 (psu.edu).