4GB Memory Module for Apple iMac 27-inch (Late 2012) Core i5 Core i7 1600MHz DDR3 (PC3-12800) (PARTS-QUICK Brand) at Amazon.com
Apple's 2012 iMac: Ready for its close-up (pictures) - CNET
How to Upgrade Memory in a 27-inch iMac (Late 2012-2013) iMac13,2 and iMac14,2 - YouTube
A-Tech 8GB Kit (2x4GB) RAM for Apple MacBook Pro (Mid 2012), iMac (Late 2012, Early/Late 2013, Late 2014, Mid 2015), Mac Mini (Late 2012) | DDR3 1600MHz PC3-12800 SODIMM 204-Pin Memory Upgrade at Amazon.com
How to Upgrade/Install Memory in a 21.5-inch iMac (Late 2012– Mid 2014) iMac14,1 iMac14,3 - YouTube
Memory Upgrades for iMac 21.5-Inch 2012 - Late 2013
How to Upgrade iMac Hard Drive or SSD 2012-2022: EveryMac.com
Install memory in an iMac - Apple Support
Apple iMac (Late 2012) review (21.5- and 27-inch) | Macworld
Install memory in an iMac - Apple Support
How to Upgrade Memory in a 27-inch iMac (Late 2012-2013) iMac13,2 and iMac14,2 - YouTube