[465] Forssell 1885, p. 24.

[466] Riddle 1910.

[467] Babikoff 1878.

[468] Th. M. Fries 1866.

[469] Winter 1877.

[470] Schneider 1897.

[471] Etard and Bouilhac 1898.

[472] Hue 1910.

[473] Sernander 1907.

[474] Bitter 1904.