Replacing a swollen iPhone 4 battery — The Evil Boss
Original Battery 4s for Apple iPhone 4S A1431, A1387, A1387 Mobile Battery with 6 Month Warranty and high Capacity Battery Backup.Carefully Check Your Phone Model and Purchase. (for iPhone 4s) : Amazon.in:
OEM Apple iPhone 4S Battery - ETrade Supply
Apple iPhone 4S Battery - PHONEDOCTORS®
Apple Batteries: Apple 616-0513 - Apple iPhone 4 4G OEM Li-Ion Replacement Battery - CPU Medics
Looking inside an iPhone 4/4S battery | Rip It Apart - Jason's electronics blog-thingy