How to Upgrade Memory in a 21.5-inch or 27-inch iMac (Mid 2010) - YouTube
RAM upgrade considerations for iMac systems - CNET
Install memory in an iMac - Apple Support
Apple iMac 27-inch (Nvidia GeForce GTX 675M) - Review 2013 - PCMag UK
Harder, better, faster, stronger: A review of the 27-inch iMac | Ars Technica
How to Upgrade iMac RAM (21.5" and 27" Aluminum): EveryMac.com
A-Tech 16GB (2x8GB) 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 Kit at Amazon.com