Can I upgrade the RAM of the MacBook Pro 13' Retina from 8gb to 16gb after/during purchase? - Quora
How To Upgrade RAM On MacBook Air? - YouTube
Apple Macbook RAM Upgrades (2006 - 2010) - OWC
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