A-Tech 32GB Kit (4x8GB) RAM for Apple iMac (Late 2012, Late 2013, Late 2014, Mid 2015) | DDR3 1600MHz SODIMM PC3-12800 204-Pin SO-DIMM Max Memory Upgrade at Amazon.com
How Much RAM Do You Need? - MacFinder Blog
Install memory in an iMac - Apple Support
32GB Kit (4 x 8GB) PC3-12800 RAM for Apple iMac Late 2014 - 27 Inch Retina
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
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
Install memory in an iMac - Apple Support
Apple iMac 2014 (Mid) Core i5 1.4Ghz 21.5-inch 14,4 SSD & macOS X Upgrades - ZD Laptop Service Centre
Apple iMac 2014 (Late) 27-inch (Retina 5K) SSD ,Ram & OSX Upgrades - ZD Laptop Service Centre