8GB -2x4GB Memory Ram Upgrade 27" Apple iMac 10.1 3.06GHz Core2Duo Late 2009 | eBay
A-Tech for Apple 6GB Kit (1x2GB + 1x4GB) DDR2 667MHz PC2-5300 200-pin SODIMM for MacBook (Late 2007, Early 2008, Early 2009), MacBook Pro (Mid 2007, Early 2008), iMac (Mid 2007) - Memory RAM Upgrade at Amazon.com
Early 2009 model iMac Computer, DDR3 8GB (2x4GB) RAM Replacement - YouTube
How to Upgrade iMac RAM (21.5" and 27" Aluminum): EveryMac.com
iMac RAM for Model 11.2 to 12.2 | DDR3-1066MHz | 4GBx2 | MacMemory.com
A-Tech for Apple 2GB DDR3 1067MHz / 1066MHz PC3-8500 SODIMM Memory RAM Module for MacBook, MacBook Pro, iMac, Mac Mini - (Late 2008, Early 2009, Mid 2009, Late 2009, Mid 2010) Models at Amazon.com