[815] Knop and Schnederman 1846.

[816] Hesse 1904.

[817] Zopf 1907, p. 179.

[818] Zopf 1907.

[819] Senft 1907.

[820] Tobler 1909.

[821] Keegan 1907.

[822] Schwarz 1880, p. 264.

[823] Schwendener 1863, p. 180.

[824] Fünfstück 1902.