J. Partsch, Central Europe, pp. 227-230. London, 1903.
Elisée Reclus, The Earth and Its Inhabitants; Europe, Vol. 1, pp. 370-372. New York, 1886.
Ernst Curtius, History of Greece, Vol. I, pp. 15-20. New York.
Heinrich von Treitschke, Politik, Vol. 1, p. 215. Leipzig, 1897.
H. J. Mackinder, Britain and the British Seas, pp. 35, 40. London, 1902.
William Morris Davis, Physical Geography, pp. 115-122. Boston, 1899.
Ratzel, History of Mankind, Vol. III, p. 95. London, 1896-1898.
Strabo, Book XVII, chap. I, 18. Diodorus Siculus, Book I, chap. III, p. 36. London, 1814.
J. Partsch, Central Europe, pp. 96-98. London, 1903. Ratzel, Deutschland, pp. 143-144. Leipzig, 1898.
For geomorphology of coasts, see William Morris Davis, Physical Geography, pp. 112-136, 347-383. Boston, 1899.