Timetec 8GB Compatible for Apple DDR3 1333MHz PC3-10600 CL9 for Mac Book Pro (Early/Late 2011 13/15/17 inch), iMac (Mid 2010, Mid/Late 2011 21.5/27 inch), Mac Mini(Mid 2011) SODIMM MAC RAM Upgrade : Amazon.ca: Electronics
How-To: Boost your Mac's speed and prolong its useful life with easy RAM upgrades - 9to5Mac
Timetec 32GB KIT(4x8GB) Compatible for Apple DDR3 1333MHz PC3-10600 CL9 for iMac (Mid 2010 27 inch, Mid 2011 21.5/27 inch) SODIMM Memory Module MAC RAM Upgrade for iMac 11,3 / iMac 12,1 / iMac 12, 2 : Amazon.com.au: Computers
OWC 16GB (2x8GB) ram Upgrade PC3-12800 DDR3L 1600MHz sodimm 204 Pin CL11 Memory Upgrade Kit Compatible with Late iMac, Mac Mini, and MacBook Pro Computer at Amazon.com
How to Upgrade Memory in a 21.5-inch or 27-inch iMac (Mid 2010) - YouTube
Install memory in an iMac - Apple Support
iMac 21.5" Mid 2011 How To Change/Upgrade Your Ram For Better Performance 2014 - YouTube
Install memory in an iMac - Apple Support
Imac 27 Inch 2011 Ram Upgrade Best Sale, SAVE 46% - piv-phuket.com