Late 2013 iMac review: Faster than before, but the gains over previous models are modest | Macworld
The Display - 21.5-inch iMac (Late 2013) Review: Iris Pro Driving an Accurate Display
late 2013 imac proccesor upgrade help | MacRumors Forums
New iMac Teardown
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
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
Install memory in an iMac - Apple Support
Best Buy: Pre-Owned Apple iMac 21.5-inch Desktop "Core i5" 2.9 (Late 2013) 8GB Memory 1TB HDD ME087LL/A