[10] "Der Stil in der technischen und tektonischen Künsten, oder praktische Æsthetik."
[11] See the excellent work, Stilfragen, p. 11.
[12] Evolution in Art, by A. C. Haddon. See especially figures 26, 27, 30, 31, 32, pp. 49-52. See also figure 106, p. 181.
[13] The Evolution of Decorative Art, by Henry J. Balfour, p. 50.
[14] Evolution in Art, by A. C. Haddon, p. 76.
[15] A word Dr. Colley March introduced to express the idea of an ornament due to structure.
[16] Stilfragen, p. 208 et seq. See also Dr. W. Worringer's really valuable contribution to this subject: Abstraktion und Einfühlung, p. 58.
[17] Abstraktion und Einfühlung, pp. 4, 8, 9, 11.
[18] Abstraktion und Einfühlung, p. 51. See also Grosse, The Beginnings of Art, pp. 166-169 et seq.