• Adegbite AL, Ward SB, Bajoria R. 2005. Perinatal outcome of spontaneously conceived triplet pregnancies in relation to chorionicity. Am J Obstet Gynecol 193(4): 14631471.
  • Barss VA, Benacerraf B. 1985. Ultrasonographic determination of chorion type in twin gestation. Obstet Gynecol 66: 779783.
  • Bessis R, Papiernik E. 1981. Echographic imagery of amniotic membranes in twin pregnancies. Prog Clin Biol Res 69A: 183187.
  • BlicksteinI, KeithL (eds). 2005. In Multiple Pregnancy: Epidemiology, Gestation and Perinatal outcome (2nd edn), Taylor & Francis: United Kingdom; 943.
  • Carroll SG, Soothill PW, Abdel-Fattah SA, Porter H, Montague I, Kyle PM. 2002. Prediction of chorionicity in twin pregnancies at 10–14 weeks of gestation. Br J Obstet Gynaecol 109(2): 182186.
  • D'Alton ME, Dudley DK. 1989. The ultrasonographic prediction of chorionicity in twin gestation. Am J Obstet Gynecol 160(3): 557561.
  • Guilherme R, Le Ray C, Vuillard E, et al. 2009. Ultrasound assessment of the prognosis in triplet pregnancies. Acta Obstet Gynecol Scand 88(4): 386390.
  • Hack KE, Derks JB, Elias SG, et al. 2008. Increased perinatal mortality and morbidity in monochorionic versus dichorionic twin pregnancies: clinical implications of a large Dutch cohort study. BJOG 115(1): 5867.
  • Hertzberg BS, Kurtz AB, Choi HY, et al. 1987. Significance of membrane thickness in the sonographic evaluation of twin gestations. Am J Roentgenol 148(1): 151153.
  • Kurtz AB, Wapner RJ, Mata J, Johnson A, Morgan P. 1992. Twin pregnancies: accuracy of first-trimester abdominal US in predicting chorionicity and amnionicity. Radiology 185(3): 759762.
  • Machin GA. 2004. Why is it important to diagnose chorionicity and how do we do it? Best Pract Res Clin Obstet Gynaecol 18(4): 515530.
  • Mahony BS, Filly RA, Callen PW. 1985. Amnionicity and chorionicity in twin pregnancies: prediction using ultrasound. Radiology 155(1): 205209.
  • Monteagudo A, Timor-Tritsch IE. 1998. In Ultrasound and Multifetal Pregnancy. Progress in Obstetric and Gynecological Sonography Series, MonteagudoA, Timor-TritschIE (eds). Parthenon Publishing Group Inc: New York, USA; 218.
  • Monteagudo A, Timor-Tritsch IE. 2000. Second- and third-trimester ultrasound evaluation of chorionicity and amnionicity in twin pregnancy. A simple algorithm. J Reprod Med 45(6): 476480.
  • Pretorius DH, Budorick NE, Scioscia AL, Krabbe JK, Ko S, Myhre CM. 1993. Twin pregnancies in the second trimester in women in an alpha-fetoprotein screening program: sonographic evaluation and outcome. AJR Am J Roentgenol 161(5): 10071013.
  • Senat MV, Deprest J, Boulvain M, Paupe A, Winer N, Ville Y. 2004. Endoscopic laser surgery versus serial amnioreduction for severe twin-to-twin transfusion syndrome. N Engl J Med 351(2): 136144.
  • Sepulveda W, Sebire NJ, Hughes K, Kalogeropoulos A, Nicolaides KH. 1997. Evolution of the lambda or twin-chorionic peak sign in dichorionic twin pregnancies. Obstet Gynecol 89(3): 439441.
  • Sepulveda W, Sebire NJ, Hughes K, Odibo A, Nicolaides KH. 1996. The lambda sign at 10–14 weeks of gestation as a predictor of chorionicity in twin pregnancies. Ultrasound Obstet Gynecol 7(6): 421423.
  • Townsend RR, Simpson GF, Filly RA. 1988. Membrane thickness in ultrasound prediction of chorionicity of twin gestations. J Ultrasound Med 7(6): 32732.