CMS 16GB (2X8GB) DDR3 12800 1600MHz Non ECC SODIMM Memory Ram Upgrade Compatible with Apple® MacBook Pro Core I5 2.5 13" Mid-2012 - A7 at Amazon.com
BHD 15, MacBook ,iMac,MacMini,MacPro OS ,SSD .RAM Upgrade, 53550543 - expatriates.com
OFFTEK 4GB Replacement Memory RAM Upgrade for Apple MacBook Pro 2.5GHz Intel Core i5 - (13-inch) (DDR3) (Mid-2012) (DDR3-12800) Laptop Memory at Amazon.com
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
Mid-2012 15" MacBook Pro Retina - upgrading to Big Sur? : r/BigSurPatcher
MacBook Pro Mid-2012 SSD and RAM Upgrade Tutorial - YouTube
Mid-2012 MacBook Pro Unibody RAM Upgrade - YouTube
2012 Macbook Pro 13" A1278 RAM Upgrade - YouTube
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
MacBook Pro (13-inch, Mid 2012) Hard Drive (and possibly RAM) replacement : r/mac
How to Install Memory in a 13-inch MacBook Pro (Mid 2012) MacBookPro9,2 - YouTube