[865] Jumelle 1892.

[866] Weir 1919.

[867] Wainio 1897, p. 16.

[868] Nienburg 1908.

[869] Metzger 1903.

[870] Bitter 1899.

[871] Wiesner 1895.

[872] Bitter 1901, p. 465.

[873] Fink 1909.

[874] Galløe 1908.