[735] Blackman 1904.
[736] Istvanffi 1895.
[737] Plowright 1889.
[738] Sappin-Trouffy 1896.
[739] Brefeld 1891.
[740] De Bary 1866, p. 7.
[741] Gilson 1893.
[742] Winterstein 1893.
[743] Gilson 1894.
[744] The chemical formula of chitin is given as C₆₀H₁₀₀N₈O₃₈, that of chitosan as C₁₄H₂₆N₂O₁₀.