Notes:
20. Williams P., Basic Human Embryology, 3rd ed., 1984, p. 64
21. Eldra Pearl Solomon, Linda R. Berg, Diana W. Martin, Claude V. Willee, Biology, 3rd ed., Saunders College Publishing, p. 1066
22. Geraldine Lux Flanagan, Beginning Life, Dorling Kindersley, London, 1996, p. 28.
23. Gerard J. Tortora, Introduction to the Human Body: Essentials of Anatomy & Physiology, p. 556
24. Geraldine Lux Flanagan, Beginning Life, Dorling Kindersley, London, 1996, p. 38
25. Science et Vie, Gérard Couly, March 1995, No.190, pp. 48-50
26. Hoimar von Ditfurth, Im Anfang War Der Wasserstoff (In the Beginning was Hydrogen), p. 126
27. Geraldine Lux Flanagan, Beginning Life, Dorling Kindersley, London, 1996, p. 42
28. Geraldine Lux Flanagan, Beginning Life, Dorling Kindersley, London, 1996, pp. 42-43
29. Richard Dawkins, The Selfish Gene, Oxford University Press, New York, 1976, p. 37
30. National Institute of Health, Researchers Discover How Embryo Attaches to the Uterus News Release, January 16, 2003 (http://www.nichd.nih.gov/new/releases/embryo.cfm)
31. Science et Vie, March 1995, No.190, pp. 21-22
32. Intimate Universe, The Human Body, Vol. 1, 1998, British Broadcasting Corporation,
33. Arthur C. Guyton, John E. Hall,, Textbook of Medical Physiology, 10th ed., Harcourt International Ed., PA, 2000, p. 946
34. Science et Vie, March 1995, No.190, pp. 119-120
35. Eldra Pearl Solomon, Linda R. Berg, Diana W. Martin, Claude V. Willee, Biology, 3rd ed., Saunders College Publishing, p. 1069.
36. Geraldine Lux Flanagan, Beginning Life, Dorling Kindersley, London, 1996, p. 73
37. Science et Vie, March 1995, No.190, p. 88
38. Science et Vie, March 1995, No.190, p. 94
39. Geraldine Lux Flanagan, Beginning Life, Dorling Kindersley, London, 1996, p. 74
40. Geraldine Lux Flanagan, Beginning Life, Dorling Kindersley, London, 1996, p. 64
41. Keith L. Moore, The Developing Human, W.B. Saunders Company, PA, 1982, p. 126
42. Science et Vie, March 1995, No.190, pp. 112-113
43. Geraldine Lux Flanagan, Beginning Life, Dorling Kindersley, London, 1996, p. 87
44. 1999-2003, Cincinnati Children's Hospital Medical Center (http://www.cincinnatichildrens.org/svc/dept-div/skin/medical.htm)
45. Laurence Pernoud, J'ettends un enfant, Pierre Horay, Paris, 1995, p. 135