NewerTech® : Batteries : NuPower® Battery for MacBook Pro 15" Retina mid 2012 to early 2013 Models
Amazon.com: A1417 Battery Only for (Mid 2012 & Early 2013) A1398 MacBook Pro - Replacement Battery for A1398 MacBook Pro 15-inch Retina (Mid 2012, Early 2013 Version) - EMC 2512 or 2673 [11.26V/99Wh] : Electronics
A1417 Laptop Battery For Apple Macbook Pro 15 Retina A1398 Mid 2012 Early 2013 | eBay
Amazon.com: iFixit Battery Compatible with MacBook Pro 15" Retina (Mid 2012/Early 2013) : Electronics