21.5-inch or 27-inch iMac (Mid 2011) Memory Installation Video - YouTube
Install memory in an iMac - Apple Support
Adamanta 16GB 4x4GB Apple Memory Upgrade for Mid 2010 iMac 21.5" and 27" DDR3 1333Mhz PC3-10600 SODIMM 2Rx8 CL9 1.5v RAM
Upgrading my Mid 2010 Imac computer | MacRumors Forums
How to Upgrade the RAM in Your iMac
Timetec 8GB KIT(2x4GB) Compatible for Apple DDR3 1067MHz / 1066MHz PC3-8500 for Mac Book, Mac Book Pro, iMac, Mac Mini (Late 2008, Early/Mid/Late 2009, Mid 2010) MAC SODIMM Memory RAM Upgrade at
Parity > imac 2010 ram upgrade, Up to 63% OFF
16GB Memory Upgrade Kit For Apple iMac 2010-2011
iMac RAM upgrade: Here's an affordable way to improve multitasking - CNET