Apple Has Fully Restored Inventory of Mid 2012 and Early 2013 MacBook Pro Batteries - MacRumors
Amazon.com: iFixit Battery Compatible with MacBook Pro 13" Unibody (Mid 2009 to Mid 2012) : Electronics
iFixit: New MacBook Pro has first 'DIY-friendly' battery replacement design since 2012 - 9to5Mac
Amazon.com: Ftenlyen A1322 A1278 Battery Replacement - A1322 Battery for MacBook Pro 13 inch Mid 2012 2010 2009 Early 2011 Late 2011 Version High-Performance and Long Lasting [ 10.95V 63.5WH ] : Electronics
Ultimate Guide on How to Upgrade Mid 2012 MacBook Pro: Faster and Better Than New! | College Lighthouse