A-Tech 4GB RAM for Apple MacBook Pro (Early/Late 2011), iMac (Mid 2010, Mid 2011, Late 2011), Mac Mini (Mid 2011) | DDR3 1333MHz PC3-10600 204-Pin SODIMM Memory Upgrade Module
Memory/ RAM Upgrades For Apple MacBook Pro 2011 from OWC
Apple MacBook Pro A1278 with 1 RAM Slot NOT WORKING - Trying to FIX - YouTube
How to Upgrade MacBook Pro RAM (2009, 2010, 2011, 2012): EveryMac.com
MacBook Pro: How to remove or install memory - Apple Support
MacBook Pro 13" Unibody Late 2011 RAM Replacement - iFixit Repair Guide
OWC 16GB (2x8GB) ram Upgrade PC3-12800 DDR3L 1600MHz sodimm 204 Pin CL11 Memory Upgrade Kit Compatible with Late iMac, Mac Mini, and MacBook Pro Computer at Amazon.com