Apple 13in Retina MacBook Pro review (2.7GHz, 256GB, Early 2015) - Macworld UK
Refurbished Apple A Grade Macbook Pro, 13.3-inch Laptop (Retina), 2.7Ghz Dual Core i5 (Early 2015) MF839LL/A 256 GB SSD, 8 GB Memory, 2560x1600 Display, Mac OS X v10.12, Sierra Power Adapter - Walmart.com
SSD Upgrades for 2013, 2014, and 2015 MacBook Pro
MacBook Air 11" (2013-2015) 13" (2013-2017) MacBook Pro Retina 13" and 15" ( 2015) SSD - iFixit Store
Is there a way to upgrade the RAM in an early 2015 MacBook Pro without voiding the warranty? - Quora
MacBook Pro with Retina display review (13-inch, 2015) | Engadget