- Insomnia: MedlinePlus Medical Encyclopedia
- Insomnia - eMedicine. Excellent academic clinical review of insomnia. Registration required.
- Insomnia – MayoClinic.com - Mayo Clinic. Thorough clinical review.
- http://www.aasmnet.org/resources/factsheets/insomnia.pdf - American Academy of Sleep Medicine (AASM). Fact sheet covering insomnia.
- Insomnia: Difficulty Falling Asleep: Sleep Disorders: Merck Manual Home Edition - Comprehensive review for insomnia.
- SleepNet Insomnia Homepage - Most comprehensive web site for sleeping disorders.
