NEMIX RAM 16GB Kit (2x8GB Upgrade) DDR3-1600 SODIMM PC3-12800 for Apple MacBook Pro Mid 2012 / iMac Late 2012 / iMac 2013, Late 2014, Mid 2015, Mac Mini Late 2012 at Amazon.com
32GB (2X16GB)Ram Upgrade for iMac Late 2012 21,5 inch? | MacRumors Forums
Memory Upgrades for iMac 21.5-Inch 2012 - Late 2013
Memory upgrade: Apple iMac 2012/2013/2014 (Howto)
Timetec Hynix Ic Apple 16Gb Kit (2X8Gb) Ddr3L 1600Mhz Pc3L-12800 Sodimm Memory Upgrade For Macbook Pro13-Inch/15-Inch Mid 2012, Imac 21.5-Inch : Amazon.in: Computers & Accessories
Apple iMac (Late 2012) review (21.5- and 27-inch) | Macworld