Virtual Library of Biochemistry and Cell Biology A metabolic pathway(页面存档备份,存于互联网档案馆) (Flash animation) KEGG: Kyoto Encyclopedia of Genes and Genomes(页面存档备份,存于互联网档案馆)
Baird, D. D.; Weinberg, C. R. Time of implantation of the conceptus and loss of pregnancy. The New England Journal of Medicine. 1999-06-10, 340 (23): 1796–1799