Memory RAM Upgrade for Apple iMac 21.5-inch Mid 2010 4GB DDR3 SODIMM | eBay
How to Upgrade iMac RAM (21.5" and 27" Aluminum): EveryMac.com
iMac Mid-2010 27 inch (A1312) SSD and RAM disassembly and upgrade - Much FASTER! - YouTube
RAM upgrade considerations for iMac systems - CNET
iMac RAM for Model 11.2 to 12.2 | DDR3-1066MHz | 4GBx2 | MacMemory.com
Is it worth it to upgrade RAM on Mid 2010 21.5 iMac? | MacRumors Forums
How to Upgrade iMac RAM (21.5" and 27" Aluminum): EveryMac.com
Timetec 8GB KIT(2x4GB) Compatible for Apple DDR3 1067MHz / 1066MHz PC3-8500 CL7 for Mac Book,
Amazon.com: Timetec 8GB KIT(2x4GB) Compatible for Apple DDR3 1333MHz PC3-10600 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) RAM Upgrade : Electronics
iMac RAM Models 11.3 (i5 and i7 only) to 12.2 (8GBx4) | MacMemory.com