How to Upgrade Memory in a 27-inch iMac (Late 2012-2013) iMac13,2 and iMac14,2 - YouTube
8GB -2x4GB Memory Ram Upgrade 21.5" Apple iMac-14.3 Core i5 2.9GHz Late 2013 | eBay
Apple iMac (21.5-inch, Late 2013) 8GB RAM, 1TB HDD Sell on Consignment - One Bite Technology - St. Albert
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
Installare la memoria in un iMac - Supporto Apple (IT)