New MacBook Pro makes DIY upgrades and repairs tough
Memory RAM Upgrades for MacBook Pro (2012 - Late 2016)
Teardown of Mid-2012 MacBook Air Reveals Tweaked SSD Connector - MacRumors
Adamanta 16GB (2x8GB) Apple Memory Upgrade DDR3L 1600MHz SODIMM Compatible for iMac (Mid 2011, Late 2012, Early/Late 2013, Late 2014, Mid 2015), MacBook Pro (Early/Late 2011, Mid 2012), Mac Mini at Amazon.com
MacBook Pro 15" Unibody Mid 2012 Teardown - iFixit
MacBook Pro 15" Retina Display Mid 2012 Teardown - iFixit
Memory RAM Upgrades for MacBook Pro (2012 - Late 2016)
How to upgrade the RAM on your 13-inch MacBook Pro