MacBook Pro: How to remove or install memory - Apple Support
Adamanta 16GB (2x8GB) Apple Memory Upgrade DDR3L 1600MHz SODIMM Compatible for iMac (Mid 2011, Late 2012, Early/Late 2013, Late 2014, Mid 2015), MacBook Pro (Early/Late 2011, Mid 2012), Mac Mini at Amazon.com
MacBook Pro: How to remove or install memory - Apple Support
APPLE MACBOOK PRO (13-INCH, EARLY 2011) Intel i5-2415M 2.30GHz 4GB RAM 320GB HDD | eBay
Amazon.com: Timetec 16GB KIT(2x8GB) Compatible for Apple DDR3 1333MHz PC3-10600 CL9 for Mac Book Pro (Early/Late 2011 13/15/17 inch), iMac(Mid 2010, Mid/Late 2011 21.5/27 inch), Mac Mini(Mid 2011) MAC RAM Upgrade :
How to Upgrade MacBook Pro RAM (2009, 2010, 2011, 2012): EveryMac.com
MacBook Pro 13" Unibody Early 2011 RAM Replacement - iFixit Repair Guide
Upgrade the MBP MC724 Early 2011 — Hi, I am Benny
How to Upgrade RAM in MacBook Pro 17" 2011 16GB Install Tutorial - YouTube
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
MacBook Pro 13" Unibody Early 2011 RAM Replacement - iFixit Repair Guide
MacBook Pro 13" Unibody Early 2011 RAM Replacement - iFixit Repair Guide
Amazon.com: Timetec 8GB KIT(2x4GB) Compatible for Apple DDR3L 1600MHz for Mac Book Pro (Early/Late 2011,Mid 2012), iMac(Mid 2011,Late 2012,Early/Late 2013,Late 2014,Mid 2015), Mac Mini(Mid 2011,Late 2012) MAC RAM : Electronics
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
Apple MacBook Pro Early 2011 Crucial Memory Upgrade - YouTube
MacBook Pro 15" Unibody Early 2011 RAM Replacement - iFixit Repair Guide