1. International statistical classification of diseases and related health problems;World Health Organization (WHO),1992
2. Appendix D: standard terminology for reporting of reproductive health statistics in the United States;American Academy of Pediatrics/American College of Obstetricians and Gynecologists,2007
3. Rethinking the definition of term pregnancy;Fleishman;Obstet Gynecol,2010
4. Williams obstetrics;Williams,1903
5. Chapter 4: the low-birth weight infant;Drillien,1974