MedlinePlus: Norethindrone - Features information about dosage, usage, warnings, and side effects. - http://www.nlm.nih.gov/medlineplus/druginfo/medmaster/a604034.html
Aygestin - Full prescribing information from RxList. - http://www.rxlist.com/cgi/generic2/norethindrone.htm
Micronor - Full prescribing information from RxList. - http://www.rxlist.com/cgi/generic2/norethin.htm