1. Schwalbe, E.: Die Morphologie der Missbildungen des Menschen und Tiere, Jena, 1910-12, Teil III, Lief, VIII, pp. 817-857.
2. Quoted in Luciani's Physiology;Valsalva,1911
3. Quoted in Luciani's Physiology;Müller,1911
4. The Effect of Obstructed Respiration on Heart and Lungs: Its Clinical Importance in Radiography;Crowden;Brit. M. J.,1929
5. On the Development of the Aortae, Cardinal and Umbilical Veins and the Other Blood Vessels of Vertebrate Embryos from Capillaries;Evans;Anat. Rec.,1909