[215] Lindau 1895¹.

[216] Peirce 1899.

[217] Claassen 1914.

[218] Frank 1876.

[219] Lindau 1895.

[220] Bachmann 1913.

[221] Cunningham 1879.

[222] Ward 1884.

[223] Jennings 1895.

[224] Fitting 1910.