16GB (2X8GB) SODIMM RAM Memory for Apple MacBook Pro Core i5 2.3 13" Early 2011 DDR3-10600 1333Mhz by Xtremeram at Amazon.com
Apple MacBook Pro Late 2011 8GB Memory & SSD Upgrade - YouTube
How to Upgrade MacBook Pro RAM (2009, 2010, 2011, 2012): EveryMac.com
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
Memory RAM Upgrade for Apple MacBook Pro 13-inch Late 2011 4GB DDR3 SODIMM | eBay
Rasalas 8GB Kit (2X 4GB) PC3-10600 DDR3 1333 MHz SODIMM RAM Upgrade for AMD Intel Laptop, MacBook Pro 13/15/17 inch Early/Late 2011,iMac 21.5-inch Mid/Late 2011,27-inch Mid 2011,Mac Mini 5,1 & 5,2 Mid
MacBook Pro 15" Unibody Early 2011 RAM Replacement - iFixit Repair Guide
OWC 8GB (2 x 4GB) PC12800 DDR3L 1600MHz SO-DIMMs Memory Compatible with 2011-2015 iMac,
MacBook Pro 15" Unibody Early 2011 RAM Replacement - iFixit Repair Guide
MacBook Pro 13" Unibody Early 2011 RAM Replacement - iFixit Repair Guide
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