MLA
Andrew, James O. (James Osgood), 1794-1871. Letter from James O. Andrews (Oxford, Georgia) to Robert Paine (Mobile, Alabama) - January 16, 1850. January 16, 1850. Robert Paine Papers, 1828-1882. Pitts Theology Library. https://digital.library.emory.edu/purl/52259zw4t3-cor.
APA, 6th edition
Andrew, James O. (James Osgood), 1794-1871. (January 16, 1850)[Letter from James O. Andrews (Oxford, Georgia) to Robert Paine (Mobile, Alabama) - January 16, 1850]. Robert Paine Papers, 1828-1882, Pitts Theology Library. https://digital.library.emory.edu/purl/52259zw4t3-cor.
Chicago
Andrew, James O. (James Osgood), 1794-1871, Letter from James O. Andrews (Oxford, Georgia) to Robert Paine (Mobile, Alabama) - January 16, 1850, January 16, 1850, Robert Paine Papers, 1828-1882, Pitts Theology Library. https://digital.library.emory.edu/purl/52259zw4t3-cor.