1. Exodus 15:23–25.
2. Aristotle, Works, (Clarendon Press, London, 1927 ), Vol. 7, p. 933b.
3. H. S. Thompson, J. Roy. Agr. Soc. Engl., Vol. 11 (1850), p. 68.
4. J. T. Way, J. Roy. Agr. Soc. Rngl., Vol. 11 (1850), p. 313; Vol. 13 (1852), p. 123.
5. R. Gans, Jahrb Preuss, geol. Landesanstalt, Vol. 26 (1905), p. 179.