6Mason RJ , Williams MC , Moses HL, et al . Stem cells in lung develo prment, disease, and therapy[J]. Am J Respir Cell Mol Biol, 1997, 16(4): 355-63.
7Watt FM, Hogan BL. Out of eden: stem cells and their niches[J].Science,2000, 287(5457): 1427-30.
8Enver T, Greaves M. Loops, lineage, and leukemia[J]. Cell,1998,94(1):9-12.
9Shah NM, Groves AK, Anderson DJ. Alternative neural crest cell fates are instructively promoted by TGFbeta superfamily members [ J ]. Cell,1996,85(3) :331-43.
10Peifer M. Signal transduction. Neither straight nor narrow[J]. Nature,1999,400(6741 ): 213-5.