MacBook Pro 13" Retina Display Late 2013 Teardown - iFixit
MacBook Pro 13" Retina Display Early 2015 SSD Replacement - iFixit Repair Guide
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
Apple Logic Board, 2.8GHz 16GB for MacBook Pro Retina 13" Mid 2014 A1502, (661-00610) - Apple Force
Upgrading 2013/2014 Macbook Pro SSD to M.2 NVMe | MacRumors Forums
How to Upgrade MacBook Pro RAM (2009, 2010, 2011, 2012): EveryMac.com
Timetec Hynix IC 8GB KIT(2x4GB) Compatible for Apple DDR3L 1600MHz PC3L-12800 for Early/Mid/Late 2011, Mid/Late 2012, Early/Late 2013, Late 2014, Late 2015 MacBook Pro, iMac, Mac Mini (8GB KIT(2x4GB)) - Walmart.com
Is there a way to upgrade the RAM in an early 2015 MacBook Pro without voiding the warranty? - Quora