Archibald Little, The Far East, pp. 35, 45. Oxford, 1905.

Strabo, Book X, chap. II, 19.

Ratzel, Die Erde und das Leben, Vol. I. pp. 312-313. Leipzig, 1901.

Charles H. Hawes, In the Uttermost East, p. 103. New York, 1904.

W.E. Griffis, The Mikado's Empire, Vol. I, pp. 26-27. New York, 1904.

Darwin, Origin of Species, Vol. II, chap. XIII, p, 178. New York, 1895.

A.R. Wallace, Geographical Distribution of Animals, Vol. II, p. 61. London, 1876.

Darwin, Origin of Species, Vol. II, chap. XIII, p. 183. New York, 1895.

Ibid., Vol. II, chap. XIII, pp. 178-180.

A.R. Wallace, Island Life, pp. 331-332, 338-389, 393, 402, 409-410, 449, 456-463. New York, 1893.