Apple MacBook Pro with Retina Display (15-inch, 2014) review: Still the best higher-res laptop, but the competition is catching up - CNET
Upgrading Ram in a Macbook Pro 13" | How to Upgrade Ram on 13" Macbook Pro - YouTube
Late-2013 15-Inch Retina MacBook Pro Review: Apple's High-Performance Notebook Tops The Field | TechCrunch
Apple Macbook Pro Retina Late 2013 15" - ME874LL/A - MacBookPro11,3 - A1398 - 2745
MacBook Pro (Retina, 15-inch, Late 2013) - Technical Specifications
Review: Apple's late-2013 15-inch MacBook Pro with Retina display | AppleInsider
Retina, round two: Apple's 15-inch 2013 Retina MacBook Pro reviewed | Ars Technica
How to Upgrade RAM on MacBook Pro, iMac & More | AVG
How to Upgrade MacBook Pro RAM (2009, 2010, 2011, 2012): EveryMac.com
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
Apple MacBook Pro (15-inch, 2013) review: Apple's high-end laptop gets better battery life and a lower price - CNET
MacBook Pro - Wikipedia
macbook pro - Can I upgrade RAM on late 2013 retina Mac Book Pro? - Ask Different