Amazon.com: PCIe NVMe Gen3x4 SSD 1TB 512GB 256GB 128GB 3D TLC NAND Flash Hard Drive SSD Replacement for Macbook Air 2013-2017, Macbook Pro Retina 2013-2015, iMac 2013-2017, Mac Pro 2013, Mac Mini 2014 (1TB) : Electronics
How to Upgrade the PCIe SSD in a 15-inch MacBook Pro w/ Retina display (Late 2013 - Mid 2015) - YouTube
MacBook Pro Retina (Mid 2012): SSD Replacement - YouTube
MacBook Pro 15" Retina Display Mid 2014 Repair - iFixit
MacBook Pro Retina 13 and 15-inch Late 2013 - Mid 2014 SSD upgrade - Flexx memory
Amazon.com: Odyson - 128GB SSD Replacement for MacBook Pro 13" Retina A1502, 15" A1398 (Late 2013, Mid 2014) : Electronics
SSD Upgrades for 2013, 2014, and 2015 MacBook Pro
MacBook Pro 15" Retina Display Mid 2014 Repair - iFixit