1. Topinard P.: Anthropology. Chapman and Hall, London; J. B. Lippincott and Co., Philadelphia, 1878, p. 256–257.
2. Deniker J.: The Races of Man. Charles Scribner and Sons, New York; Second Edition, Walter Scott Publishing Co., Ltd., London, 1912, p. 80.
3. Schaeffer J. P.: The Nose and Olfactory Organ in Man. P. Blakiston's Son and Co., Philadelphia, 1920, p. 62.
4. Hrdlicka Ales: Practical Anthropometry. Third Edition, The Wistar Institute of Anatomy and Biology, Philadelphia, 1947, p. 211–213.
5. Martin R.: Lehrbuch der Anthropologic Jena, Fischer, 1914, from Hrdlicka above, p. 211–213.