Configure your own 21.5-inch Apple iMac (2013) at OWC
Apple iMac 21.5" Late 2013 Core i5 8GB RAM 250gb SSD - VESA Mount Only NO STAND | eBay
Install memory in an iMac - Apple Support
late 2013 imac proccesor upgrade help | MacRumors Forums
Memory Upgrades for iMac 21.5-Inch 2012 - Late 2013
iMac | 3.2 GHz Core i5 | 27 Inch | Late 2013 - Techable.com
16GB -2x8GB Memory Ram Upgrade 21.5" Apple iMac-14.1 Core i5 2.7GHz Late 2013 | eBay
Teardown of new 21.5-inch iMac surprisingly reveals user-upgradable RAM, modular CPU - 9to5Mac
Memory upgrade: Apple iMac 2012/2013/2014 (Howto)
Apple iMac 2013 (Late) 21.5-inch (iMac 14,3) SSD ,Ram & OSX Upgrades - ZD Laptop Service Centre
Apple iMac 21.5" All-in-One Desktop Computer Core i5-4570R 2.7GHz 8GB RAM 250GB HDD Mac OS Mojave Late-2013 w/ Keyboard & Mouse
iMac Late 2013 21.5 SSD Upgrade - YouTube
Amazon.com: Apple iMac 21.5in 2.7GHz Core i5 (ME086LL/A) All In One Desktop, 8GB Memory, 256GB Solid State Drive, MacOS 10.12 Sierra (Renewed) : Electronics
Differences Between Late 2012 and Late 2013 Aluminum iMac: EveryMac.com
How to Upgrade/Install Memory in a 21.5-inch iMac (Late 2012– Mid 2014) iMac14,1 iMac14,3 - YouTube
The Display - 21.5-inch iMac (Late 2013) Review: Iris Pro Driving an Accurate Display
New iMac Teardown
Install memory in an iMac - Apple Support
21.5 inch late 2013 iMac - RAM upgrade - Apple Community