Configure your own 13-inch Apple MacBook Pro (2012) at OWC
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
MacBook Pro (13-inch, Mid 2012) Hard Drive (and possibly RAM) replacement : r/mac
Apple MacBook Pro 13" A1278 mid 2012 (EMC 2554) Notebook - 1529939 | furbify
Upgrade Your Macbook Pro (SSD Upgrade, RAM Upgrade, Optical Drive Bay Adapter) - YouTube
Apple MacBook Air "Core i5" 1.8 13" (Mid-2012) A1466 MD231LL/A – Coretek Computers
MacBook Pro: How to remove or install memory - Apple Support
Mid 2012 13" inch MacBook Pro A1278 Disassembly RAM SSD Hard Drive Upgrade Repair OSX Install - YouTube