SleepLikeTheDead.com: According to this article -- which editors say is based on data from more than 5,600 owners -- about 81 percent of owners are happy with their memory foam mattresses (a higher percentage than for any other mattress type).
MyFoamMattress.net: Daniel Burrows and Liz Hoffman have compiled several pages of information on memory foam mattresses and how they measure up against other types.
Choice magazine: This mattress buying guide from Choice, a publication of the Australian Consumers' Association, focuses on innerspring mattresses, but it does provide some useful information about memory foam in the section on alternatives.
Which? magazine: This buying guide from the U.K.'s Which?
New York Magazine: Sarah Bernard describes her experiences testing 100 memory foam, latex and hybrid mattresses.
ConsumerReports.org: Editors poll more than 17,000 subscribers who have purchased mattresses in the past few years to ask about their satisfaction with both the brand they chose and the store where they made the purchase.
Choice magazine: In this report, the editors of Choice magazine poll mattress buyers to see how satisfied they are with their purchases.
What's the Best Mattress: This website as a whole focuses chiefly on innerspring mattresses, but this page offers a brief discussion of memory foam mattresses.
Memory Foam Mattress.org: MemoryFoamMattress.org aims to be a source for shoppers looking for the best foam mattress to fit their needs.
Spine: This study compares outcomes in 160 patients with chronic lower back pain when sleeping on a hard mattress, a memory foam mattress and a waterbed.
WebMD.com: Charlene Laino interviews several sleep experts, including orthopedic physicians and a physical therapist, about their mattress recommendations.
Epinions.com: Of the more than 200 mattresses at Epinions.com, the two top-rated brands are memory foam mattresses: Bergad Isoform and Bragada Crowne (discontinued).