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
iMac RAM for Model 11.2 to 12.2 | DDR3-1066MHz | 8GB | MacMemory.com
How I kept my iMac running for a decade | Cult of Mac
Install memory in an iMac - Apple Support
Apple iMac 21.5" - Early 2010 Reviews, Pros and Cons | TechSpot
Apple iMac 21.5" - Early 2010 Reviews, Pros and Cons | TechSpot
Amazon.com: Timetec 16GB KIT(2x8GB) 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) MAC RAM Upgrade :
How-To: Boost your Mac's speed and prolong its useful life with easy RAM upgrades - 9to5Mac
OWC Performance Upgrades for iMac 2010
8GB kit (2x4GB) DDR3 1066 SODIMM for Apple iMac (2009), MacBook Pro (2 – Aplus Technology