Late 2012/ 2013/2014 & Early 2015 iMac Retina 5k – SimplyMac SG
HOW I UPGRADED MY iMAC 21.5in Late 2013 MODEL (SSD & RAM UPGRADE) - YouTube
Configure your own 21.5-inch Apple iMac (2013) at OWC
Memory upgrade: Apple iMac 2012/2013/2014 (Howto)
iMac RAM upgrade: Here's an affordable way to improve multitasking - CNET
iMac 2013 Model Ram Upgrade - YouTube
Apple Posts iMac (Late 2013) Memory Specifications
A-Tech 8GB RAM for Apple MacBook Pro (Mid 2012), iMac (Late 2012, Early/Late 2013, Late 2014, Mid 2015), Mac Mini (Late 2012) | DDR3 1600MHz PC3-12800 SODIMM 204-Pin Memory Upgrade at Amazon.com
Install memory in an iMac - Apple Support
2013 iMac teardowns reveal SSD slots, soldered-in CPU in the 21.5” model | Ars Technica
Come aggiungere o sostituire RAM iMac - FASTWEBPLUS
21.5-inch iMac (Late 2013) Review: Iris Pro Driving an Accurate Display