Amazon.com: GHU New Battery Replacement for A1331 Compatible with Apple MacBook Unibody 13 A1342 (Late 2009& Mid 2010) MC516LL/A MC207LL/A Battery Only fit 661-5391 10.8V 58 Wh : Electronics
How To: Replace the Battery in a Macbook Pro 13" Unibody - YouTube
For Apple MacBook Pro Unibody 15" A1286 Mid-2009 2010 A1321 Replacement Battery | eBay
Amazon.com: iFixit Battery Compatible with MacBook Pro 13" Unibody (Mid 2009 to Mid 2012) : Electronics
NewerTech® : Batteries : NuPower® Batteries for MacBook® Pro 15-inch Unibody (2008/2009)