This undated photo provided by permission of the Houghton Library at Harvard University in Cambridge, Mass., shows one of two pages (call number MS Am 1326) from the library's archives

 

              This undated photo provided by permission of the Houghton Library at Harvard University in Cambridge, Mass., shows one of two pages (call number MS Am 1326) from the library
This undated photo provided by permission of the Houghton Library at Harvard University in Cambridge, Mass., shows one of two pages (call number MS Am 1326) from the library's archives that Illinois State University math professors Nerida Ellerton and Ken Clements on Friday, June 7, 2013, confirmed as two new pages to add to the math notebook believed to be the oldest surviving document written by Abraham Lincoln. The pages are from the 1820s. Lincoln's stepmother gave the notebook to Lincoln law partner William Herndon after the 16th president's death. (AP Photo/With permission of the Houghton Library, Harvard University)