5Wiiss M J, Orkin SH. In vitro differentiation of murine embryonic stem cells : new approachs to old problems. J Clin Invest, 1996,97 : 91-595.
6Jones-Villeneuve EM, McBumey M W, Rogers KA, et al. Retinoic acid induces embryonal carcinoma cells to differentiate into neurons and glial cells. J Cell Biol, 1982,94(2) :253.
7Rohwedel J, Guan K, Wobus AM, et al. Induction of cellular differentiation by retinoic acid in vitro. Cells Tissues Organs, 1999,165: 190-202.
8Bain G, Kitchens D, Yao M, et ah Embryonic stem cells express neuronal properties in virto. Dev Biol,1995,168(2) :342.
9Wichterle H, Lieberama, Porter JA, et al. Directed differentiation of Embryonic Stem Ceils into Motor Neurons Cell,2002,110 (9) :385- 397.
10Li XY, Du ZW, Zaronwska ED, et al. Srlecification of motoneurons from human embryonic stem cells. Nature Biotechnology, 2005,23 (2) :215-221.