Apple MD101LL/A MacBook Pro MID-2012 13.3 Inches Core I5 2.5GHz 4GB RAM 500GB Refurbished – Computechsale
How to Upgrade MacBook Pro RAM (2009, 2010, 2011, 2012): EveryMac.com
Memory RAM Upgrades for MacBook Pro (2012 - Late 2016)
Samsung ram Memory 8GB kit (2 x 4GB) DDR3 PC3-12800,1600MHz for 2012 Apple MacBook Pro's, iMac's and 2011/2012 Mac Mini's at Amazon.com
LOGIC BOARD For 15" MacBook Pro Retina A1398 Mid 2012
A-Tech 16GB Kit (2x8GB) 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
Does the mid-2012 13 MacBook Pro have an M.2 slot that I can use for an Intel Optane memory upgrade? - Quora
NEMIX RAM 16GB Kit (2x8GB Upgrade) DDR3-1600 SODIMM PC3-12800 for Apple MacBook Pro Mid 2012 / iMac Late 2012 / iMac 2013, Late 2014, Mid 2015, Mac Mini Late 2012 at Amazon.com
Is upgrading the mid-2012 MacBook Pro Worth It? - Learn Robotics