Template:Ref-O'Rahilly1985
From Embryology
O'Rahilly R. and Muller F. The origin of the ectodermal ring in staged human embryos of the first 5 weeks. (1985) Acta Anat., 122: 145-157.
O'Rahilly R. and Muller F. The origin of the ectodermal ring in staged human embryos of the first 5 weeks. (1985) Acta Anat., 122: 145-157.