Authentication Score 3
Original Citation
Darwin, Charles. Letter to J. D. Hooker. 13 July 1856.
Current Citation
Darwin, Charles. "To J. D. Hooker, 13 July 1856." The Correspondence of Charles Darwin, edited by Frederick Burkhardt and James A. Secord. Vol. 6: 1856-1857. Cambridge University Press, 1990, no. 1924.