Memory Upgrades for iMac 27-Inch (2012 - Mid 2015)
How to Upgrade iMac RAM: 2012-2020: EveryMac.com
Memory Upgrades for iMac 27-Inch (2012 - Mid 2015)
Install memory in an iMac - Apple Support
A-Tech 16GB (2x8GB) PC3-12800 DDR3 1600MHz RAM for Apple MacBook Pro (Mid 2012), iMac (Late 2012, Early/Late 2013, Late 2014, Mid 2015), Mac Mini (Late 2012) | 204-Pin SODIMM Memory Upgrade - Walmart.com - Walmart.com
Timetec Hynix IC Apple 8GB DDR3L 1600MHz PC3L-12800 SODIMM Memory upgrade For MacBook Pro 13-inch/15-inch Mid 2012, iMac 21.5-inch Late 2012/ Early/ Late 2013 (8GB) - Walmart.com
Apple Officially Confirms 21.5” iMac RAM Is Non-User-Replaceable
Memory Upgrades for iMac 21.5-Inch 2012 - Late 2013
Install memory in an iMac - Apple Support
iMac RAM upgrade: Here's an affordable way to improve multitasking - CNET
How to Upgrade RAM on MacBook Pro, iMac & More | AVG
OWC 8GB RAM Kit (2x4GB) iMac Late 2012 tot Mid 2015 - 4mac