How to upgrade RAM / Memory on a 2010 iMac Core i3 i5 i7 (21.5in & 27in) - YouTube
How to Upgrade Memory in a 21.5-inch or 27-inch iMac (Mid 2010) - YouTube
iMac Upgrade Guide for Intel iMacs
RAM upgrade considerations for iMac systems - CNET
Install memory in an iMac - Apple Support
Memory Upgrades for iMac 21.5-Inch 2012 - Late 2013
Mac Pro Mid 2010 Memory Upgrade for Model 5.1 12-Core | MacMemory.com
32.0GB OWC Memory Upgrade Kit For 2010-2011 Apple iMac
Mac mini Mid 2010 RAM Replacement - iFixit Repair Guide
Timetec Hynix IC 16GB KIT(2x8GB) Compatible for Apple DDR3 PC3-8500 1067MHz/1066MHz Upgrade for MacBook 13'' Mid 2010, MacBook Pro 13'' Mid 2010, iMac 27''Late 2009, Mac Mini Mid 2010(16GB KIT(2x8GB)) - Newegg.com
Amazon.com: OWC 16GB (4 x 4GB) PC8500 DDR3 1066MHz SO-DIMMs Memory Compatible with iMac 21.5" and 27" (October/2009) : Everything Else
16GB -2x8GB Memory Ram Upgrade for 27" Apple iMac-11.3 Core i5 3.6GHz Mid 2010 | eBay
A-Tech 8GB RAM for Apple MacBook Pro (Early/Late 2011), iMac (Mid 2010 27 inch 4-Core, Mid 2011 21.5/27 inch), Mac Mini (Mid 2011) | DDR3 1333MHz PC3-10600 204-Pin SODIMM Memory Upgrade Module
CMS 16GB (4X4GB) DDR3 10600 1333MHZ Non ECC SODIMM Memory Ram Upgrade Compatible with Apple® iMac Core I3 3.06 21.5-Inch (Mid-2010) - A28 at Amazon.com