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How to Upgrade MacBook Pro RAM (2009, 2010, 2011, 2012): EveryMac.com
Macbook Pro Retina 2015 Model 8GB RAM 128GB SSD 13" inch Catalina OS 2019/2020 885909918164 | eBay
Teardown of 13" Retina MacBook Pro finds redesigned battery, Samsung flash, soldered RAM | AppleInsider