21.5 inch late 2013 iMac - RAM upgrade - Apple Community
Memory Upgrades for iMac 21.5-Inch 2012 - Late 2013
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
macbook pro - Can I upgrade RAM on late 2013 retina Mac Book Pro? - Ask Different
How to Upgrade Memory in a 27-inch iMac (Late 2012-2013) iMac13,2 and iMac14,2 - YouTube