MLA
Early, John, 1786-1873. Envelope addressed to Robert Paine (Aberdeen, Mississippi) from John Early. circa May 25, 1860. Robert Paine Papers, 1828-1882. Pitts Theology Library. https://digital.library.emory.edu/purl/460qrfj7vj-cor.
APA, 6th edition
Early, John, 1786-1873. (circa May 25, 1860)[Envelope addressed to Robert Paine (Aberdeen, Mississippi) from John Early]. Robert Paine Papers, 1828-1882, Pitts Theology Library. https://digital.library.emory.edu/purl/460qrfj7vj-cor.
Chicago
Early, John, 1786-1873, Envelope addressed to Robert Paine (Aberdeen, Mississippi) from John Early, circa May 25, 1860, Robert Paine Papers, 1828-1882, Pitts Theology Library. https://digital.library.emory.edu/purl/460qrfj7vj-cor.