1. 1915 Modern Medicine by Osler and McRae. Lea and Febiger, Philadelphia, p. 434.
2. 1930 Developmental Anatomy. W. B. Saunders Company, Philadelphia, pp. 277-277, 254-254.
3. 1866 Referred to by Poynter.
4. 1824 Traité des maladies du coeur. Referred to by Roschdestwenskij.