Real Simple
8 Firm Mattresses That Just Might Convert Plush-Mattress Sleepers: "Want the firmest of the best firm mattresses? Brooklyn Bedding’s Plank fits the bill. This all-foam bed is dual sided, offering one firm side and one extra-firm side...This mattress has very little give, so if you sleep on your back or stomach it will provide excellent spine alignment and pressure relief. It also has superior durability and edge support, meaning it will retain its plank-like shape for a long time."
