Timetec 32GB KIT(4x8GB) Compatible for Apple DDR3L 1600MHz PC3L-12800 CL11 for iMac (Mid 2011, Late 2012, Late 2013, Late 2014 Retina 5K, Mid 2015 Retina 5K) SODIMM Memory Module MAC RAM Upgrade at Amazon.com
maxupgrades.com: Dual SSD Drives kit for iMac 27 inch 2012 Models with Blade SSD Module with Heatsink and Power and DATA Cables
Apple iMac Late 2012 27-inch 2.9GHz Core i5 Desktop DDR3 RAM Memory | Kingston
Harder, better, faster, stronger: A review of the 27-inch iMac | Ars Technica
Apple iMac 27-inch (Late 2012) - Review 2012 - PCMag UK
Can you upgrade the RAM in the 27-inch iMac? | iMore
The Case of the Late-2012 iMacs - MacStories
Memory Upgrades for iMac 27-Inch (2012 - Mid 2015)
Apple iMac (Late 2012) review (21.5- and 27-inch) | Macworld
Adamanta 16GB (2x8GB) Apple Memory Upgrade DDR3L 1600MHz SODIMM Compatible for iMac (Mid 2011, Late 2012, Early/Late 2013, Late 2014, Mid 2015), MacBook Pro (Early/Late 2011, Mid 2012), Mac Mini at Amazon.com
Memory Upgrades for iMac 27-Inch (2012 - Mid 2015)