Upgrade Your Macbook Pro (SSD Upgrade, RAM Upgrade, Optical Drive Bay Adapter) - YouTube
CMS 4GB (1X4GB) DDR3 12800 1600MHz NON ECC SODIMM Memory Ram Compatible with Apple Macbook Pro 15.4" 2.3Ghz Intel Core I7 Md103Ll/A - A20 - Walmart.com
Apple Macbook Pro Laptop 15" 2.3Ghz - 3.3Ghz Core i7 - Up to 16GB & 2TB SSHD
Best Buy: Apple MacBook Pro 15.4" Display Intel Core i7, 4GB RAM 500GB HDD ( MD103LL/A) Mid-2012 Pre-Owned Silver A1286
Apple MacBook Pro A1286 15.4 inch Laptop - MD103LL/A (June, 2012) for sale online | eBay
16GB 2X8GB Memory RAM for Apple MacBook Pro MD103LL/A (15" Quad-core Intel Core i7 2.3GHz) 204pin 1600MHz PC3-12800 DDR3 SO-DIMM Black Diamond Memory Module Upgrade - Walmart.com
MacBook Pro RAM Upgrade - 16GB
Adamanta 16GB (2x8GB) Apple Memory Upgrade DDR3L 1600MHz SODIMM Compatible for iMac (Mid 2011, Late 2012, Early/Late 2013, Late 2014, Mid 2015) 2Rx8 CL11 1.35v RAM at Amazon.com
Apple MacBook Pro MD103LL/A 15.4" 4GB 500GB Core™ i7-3615QM 2.3GHz Mac – Device Refresh
A-Tech 8GB RAM for Apple MacBook Pro (Mid 2012), iMac (Late 2012, Early/Late 2013, Late 2014, Mid 2015), Mac Mini (Late 2012) | DDR3 1600MHz PC3-12800 SODIMM 204-Pin Memory Upgrade at Amazon.com
8GB PC3-12800 RAM for Apple MacBook Pro Mid 2012 - 15 Inch MD103LL/A Memory Upgrade