Streeter, G.L.1920Weight, sitting height, head size, foot length, and menstrual age of the human embryo. Contributions to embryology: No. 55. Carnegie Inst. of Wash., Pub. No. 274, pp. 145-170.
2.
Mall, F.P.1910. Manual of human embryology, Vol. I, pp. 180-201; J. B. Lippincott & Co., Philadelphia, Pa.
3.
Schultz, A.H.1929The technique of measuring the outer body of human fetuses and of primates in general. Contributions to Embryology: No. 117. Carnegie Inst. of Wash., Pub. No. 394, pp. 213-257.