1. Strong SJ, Corney G. The Placenta in Twin Pregnancy. London: Pergamon Press; 1967:1–13.
2. Kloosterman GJ. The “Third Circulation” in identical twins. Ned Tijdschr Veriosk Gynaecol.1963;63:395–412.
3. Benirschke K. Twin placenta in perinatal mortality. NY State J Med.1961;61:1499–1508.
4. Naeye RL. Human intrauterine parabiotic syndrome and its complications. N Engl J Med.1963;268:804–809.
5. Naeye RL. Organ abnormalities in a human parabiotic syndrome. Am J Pathol.1965;46:829–842.