Pre-Owned Apple iMac 21.5-inch Desktop "Core i5" 2.9 (Late 2013) 8GB Memory 1TB HDD ME087LL/A - Best Buy
2013 iMac teardowns reveal SSD slots, soldered-in CPU in the 21.5” model | Ars Technica
Memory upgrade: Apple iMac 2012/2013/2014 (Howto)
Apple's new 'Assembled in USA' iMac a bear to upgrade, repair • The Register
Apple iMac 21.5-inch and 27-inch (Late 2013) reviews | Macworld
Late 2013 iMac review: Faster than before, but the gains over previous models are modest | Macworld
iMac Late 2013 Upgrade in 2020 CPU Ssd Ram MAX Out ... Worth it? | Shades Of Tech ⬡ - YouTube
iMac RAM upgrade: Here's an affordable way to improve multitasking - CNET
A-Tech 8GB Kit (2x4GB) 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
A-Tech 32GB Kit (4x8GB) RAM for Apple iMac (Late 2012, Late 2013, Late 2014, Mid 2015) | DDR3 1600MHz PC3-12800 SODIMM 204-Pin Memory Upgrade at Amazon.com
Apple iMac 21.5" A1418 Late 2013 i5-4570R 2.7GHz Iris Pro Logic Board 820-3588-A | eBay
16GB -2x8GB Memory Ram Upgrade 21.5" Apple iMac-14.1 Core i5 2.7GHz Late 2013 | eBay
Configure your own 21.5-inch Apple iMac (2013) at OWC
21.5" Inch iMac Late 2013 A1418 RAM PCIe NVMe SSD Hard Drive Upgrade PSU Logicboard Replacement - YouTube
Memory Upgrades for iMac 21.5-Inch 2012 - Late 2013