Amazon.com: A1382 Battery Compatible with MacBook pro 15" A1286 (only for Early 2011, Late 2011, Mid 2012), fit MC721LL/A MC723LL/A 661-5844 020-7134-A 661-5211 661-5476 10.95V 77.5WH : Electronics
How to Replace the Battery in a 17-inch MacBook Pro 2011 (Updated) - YouTube
A1382 Battery for MacBook Pro 15 inch A1286 Early 2011 Late 2011 Mid 2012 New Replacement Laptop Battery (7200mAh 10.95V/78.84Wh 25 Months Warranty) Laptop Batteries / AC Adapters - Newegg.com
Amazon.com: Temark New A1382 Battery for MacBook Pro 15 inch A1286 (only for Early 2011, Late 2011, Mid 2012), fit MC721LL/A MC723LL/A 661-5844 020-7134-A : Electronics
Amazon.com: Ankon A1382 A1286 Laptop Battery for Apple MacBook Pro 15" i7 (Only for Core i7 Early 2011 Late 2011 Mid 2012 Version) MB985 MC721 661-5476 661-5211 [6-Cell 77.5WH] : Electronics
Replacing the Battery in a MacBook Pro Unibody (2009-2012) in 5 Minutes! - YouTube
MacBook Pro 13" Unibody Early 2011 Battery Replacement - iFixit Repair Guide
iFixit: New MacBook Pro has first 'DIY-friendly' battery replacement design since 2012 - 9to5Mac