Distinct Sources of Hematopoietic Progenitors Emerge before HSCs and Provide Functional Blood Cells in the Mammalian Embryo oleh Kathleen E. McGrath, Jenna M. Frame, Katherine H. Fegan, James R. Bowen, Simon J. Conway, Seana C. Catherman, Paul D. Kingsley, Anne D. Koniski, James Palis