1. Blyth A. W. (1895). Poisons: Their Effects and Detection. 3rd ed. London: Charles Griffin & Co., p. 15.
2. Christison Robert (1845). A Treatise on Poisons. 4th ed. Edinburgh: A. & C. Black, pp. 289–290.
3. Christison Robert (1885). The Life of Sir Robert Christison, Bart. Edinburgh: William Blackwood & Sons, Vol. I, pp. 240–241.