1. Atlas of Human Hematopoietic Development;Keleman,1979
2. Normal hematopoiesis in intra-uterine and neonatal life;Gilmore;J Pathol Bacteriol,1941
3. Haemopoiesis in the human yolk sac;Takashina;J Anat,1987
4. The Developing Human: Clinically Oriented Embryology;Moore,1988
5. Stem cell facts for the neonatologist;Yoder,2008