Name Info Provider Link
Insomnia free resource MedlinePlus Health Information https://medlineplus.gov/insomnia.html
subscription/membership/fee required Ovid Technologies, Inc. http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=linkout&SEARCH=8650463.ui
subscription/membership/fee required Silverchair Information Systems https://academic.oup.com/sleep/article-lookup/doi/10.1093/sleep/19.1.47