A-Tech 8GB 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 Module at Amazon.com
Amazon.com: A-Tech Components: Mid 2010 iMac
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
How to Upgrade iMac RAM (21.5" and 27" Aluminum): EveryMac.com
NEMIX RAM 32GB (4x8GB Upgrade) DDR3-1333 PC3-10600 204-Pin SODIMM Memory for Apple MacBook Pro Early/Late 2011, iMac Mid 2010 27 inch 4-Core, iMac Mid 2011 21.5/27” , Mac Mini Mid 2011 at Amazon.com