Bardsley CR (2011). "Normal Pregnancy". In Tintinalli JE, Kelen GD, Stapczynski JS (eds.). Tintinalli's Emergency Medicine: A Comprehensive Study Guide (7th ed.). New York: McGraw-Hill. Archived from the original on 2013-01-20. Retrieved 2013-06-19.
Ewertz M, Duffy SW, Adami HO, et al. (1990). "Age at first birth, parity and risk of breast cancer: A meta-analysis of 8 studies from the Nordic countries". International Journal of Cancer. 46 (4): 597–603. doi:10.1002/ijc.2910460408. PMID2145231. S2CID32387496.
Ewertz M, Duffy SW, Adami HO, et al. (1990). "Age at first birth, parity and risk of breast cancer: A meta-analysis of 8 studies from the Nordic countries". International Journal of Cancer. 46 (4): 597–603. doi:10.1002/ijc.2910460408. PMID2145231. S2CID32387496.
Ewertz M, Duffy SW, Adami HO, et al. (1990). "Age at first birth, parity and risk of breast cancer: A meta-analysis of 8 studies from the Nordic countries". International Journal of Cancer. 46 (4): 597–603. doi:10.1002/ijc.2910460408. PMID2145231. S2CID32387496.
Bardsley CR (2011). "Normal Pregnancy". In Tintinalli JE, Kelen GD, Stapczynski JS (eds.). Tintinalli's Emergency Medicine: A Comprehensive Study Guide (7th ed.). New York: McGraw-Hill. Archived from the original on 2013-01-20. Retrieved 2013-06-19.