Review: Apple's 27" big screen iMac (late 2009) | AppleInsider
Can the Late 2009 27" iMac handle 32GB of RAM? | MacRumors Forums
A-Tech 32GB (4 x 8GB) PC3-8500 DDR3 1066/1067 MHz RAM for iMac Late 2009 27- inch (Quad-Core i5/i7) | 204-Pin SODIMM Max Memory Upgrade Kit at Amazon.com
Sold - 27" iMac Late 2009 // $295 - Boulder Mac Repair
Install memory in an iMac - Apple Support
Install memory in an iMac - Apple Support
Memory Upgrades for Apple iMac 2009 - Up to 32GB
Apple iMac 3.0Ghz Core 2 Duo 21.5-Inch (Late-2009) *No HDD/RAM* – MSU Surplus Store