Norwitz ER, Schust DJ, Fisher SJ (Novembro de 2001). «Implantation and the survival of early pregnancy». The New England Journal of Medicine. 345 (19): 1400–8. PMID11794174. doi:10.1056/NEJMra000763
Norwitz ER, Schust DJ, Fisher SJ (Novembro de 2001). «Implantation and the survival of early pregnancy». The New England Journal of Medicine. 345 (19): 1400–8. PMID11794174. doi:10.1056/NEJMra000763