Tham khảo:
Nelson textbook of pediatrics,page26
http://en.wikipedia.org/wiki/Old_age
http://en.wikipedia.org/wiki/Infant
http://en.wikipedia.org/wiki/Full_term#Initiation
http://en.wikipedia.org/wiki/Middle_age
http://en.wikipedia.org/wiki/Postnatal
http://en.wikipedia.org/wiki/Fetus
http://vietlifemedical.com/vi-vn/cha...s/p/893/0.aspx