A-Tech 4GB RAM for Apple MacBook Pro (Early/Late 2011), iMac (Mid 2010, Mid 2011, Late 2011), Mac Mini (Mid 2011) | DDR3 1333MHz PC3-10600 204-Pin SODIMM Memory Upgrade Module at Amazon.com
Amazon.com: Apple MacBook Pro 13-inch MD313LL/A (4GB RAM, 500GB HD, macOS 10.13) (Renewed) : Electronics
A-Tech 4GB RAM for Apple MacBook Pro (Early/Late 2011), iMac (Mid 2010, Mid 2011, Late 2011), Mac Mini (Mid 2011) | DDR3 1333MHz PC3-10600 204-Pin SODIMM Memory Upgrade Module at Amazon.com
OWC 8GB (2 x 4GB) PC12800 DDR3L 1600MHz SO-DIMMs Memory Compatible with 2011-2015 iMac, 2011-12 Mac Mini, and 2011-2012 MacBook Pro (Non-Retina Display) Models (OWC1600DDR3S08S) at Amazon.com
Apple MacBook Pro A1286 Early-2011, 15.4-inches, Core i7, 4GB RAM, 500GB HDD, Silver - Apple Force
2010 Apple MacBook Pro 15” Laptop Intel Core i5, 500GB Storage, 4GB RAM | PCS Computers
Apple MacBook Pro 13" Late 2011 2.4Ghz Core i5 4GB RAM 500GB for Sale in Atlanta, GA - OfferUp
Apple 15-inch MacBook Pro (Late 2011) Review
macos - What is the maximum amount of RAM a 2011 MacBook Pro can utilize? - Ask Different
Apple MacBook Pro 13" Late 2011 2.4Ghz Core i5 4GB RAM 500GB for Sale in Atlanta, GA - OfferUp
Apple MacBook Pro A1278 Early 2011 Core i5-2415M 4GB 320GB 13" Read D92FFQKYDH2G | eBay
Apple MacBook Pro 13.3" Laptop - Early 2011 Model 250GB SSD 4GB RAM | eBay
Restored Apple MacBook Pro Laptop, 13.3", Intel Core i5-3210M, 4GB RAM, 500GB HD, Mac OS, Silver, MD101LL/A (Refurbished) - Walmart.com
Amazon.com: Apple MacBook Pro 13-inch MD313LL/A (4GB RAM, 500GB HD, macOS 10.13) (Renewed) : Electronics
Apple MacBook Pro 15-inch Early 2011 2GHz Intel Core i7 (MC721LL/A) – UNICOM, Inc.
APPLE MACBOOK PRO A1278 INTEL CORE I5 @ 2.3GHZ 4GB RAM 500GB HDD EARLY 2011*READ | eBay
Best Buy: Apple MacBook Pro 13.3" Intel Core i5 4GB RAM 320GB Hard Drive (MC700LL/A) Early 2011 (Certified Refurbished) Silver A1278
Apple MacBook Pro 13.3" Intel Core i5 4GB RAM - 320GB Hard Drive (MC700LL/A) Early 2011 - Silver (Fair Cosmetics, Fully Functional) - Walmart.com
MacBook Pro 15.4" is Fast! (review)
Best Buy: Apple MacBook Pro 13.3" Intel Core i5 4GB RAM 320GB Hard Drive (MC700LL/A) Early 2011 (Certified Refurbished) Silver A1278
Early 2011 Macbook Pro Upgrades | MacRumors Forums
Apple MacBook Pro 2011 15" Core i7 2.2GHz 4GB RAM 640GB HDD Dual Graphics | eBay