Những nguy cơ cho thai nhi khi mang song thai, đa thai
- Heidi Murkoff Sharon Mazel, 2008, What to expect when you’re expecting, 4th edition, Workman Publishing, USA. Page 411 – 413
- Expecting Twins? Here Are 11 Things You Should Know, && http://www.webmd.com/baby/features/11-things-you-didnt-know-about-twin-pregnancies
- Pregnant with twins: what to expect, && http://www.babycentre.co.uk/a3787/pregnant-with-twins-what-to-expect