MacBook Pro 13" Unibody Early 2011 RAM Replacement - iFixit Repair Guide
A-Tech 16GB (2x8GB) 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 Kit at Amazon.com
16GB 1333 MHz DDR3 Memory for 2011 MacBook Pro and iMac
MacBook Pro 13" Unibody Early 2011 RAM Replacement - iFixit Repair Guide
13-inch MacBook Pro Early 2011 Memory Installation Video - YouTube
Adamanta 16GB (2x8GB) Memory Upgrade Compatible for Apple Mid 2010, Early 2011, Mid 2011, Late 2011 iMac, MacBook Pro, Mac Mini DDR3 1333Mhz PC3-10600 SODIMM 2Rx8 CL9 1.5v Module RAM at Amazon.com
How to upgrade the memory in a Non-Retina 15-inch MacBook Pro 2011-2016 MacBookPro8,1 MacBookPro9,1 - YouTube