DrugDigest: Norethindrone
- Information on dosage, usage, side effects, interactions, and drug comparisons, including generics when available. Sold under brand names such as: Camila, Micronor, and Nor-QD.
- http://www.drugdigest.org/DD/DVH/Uses/0,3915,6202|Norethindrone%2Boral,00.html

Activella
- Details about the hormone replacement therapy containing estrogen and progestin derived from plants, prescribed by doctors, from Pharmacia. Includes important safety information.
- http://www.activella.com