batteries - How can I disassemble an iPhone 4 battery without damaging it? - Electrical Engineering Stack Exchange
Old iPhone 4s swelled battery. Info in comments : r/applehelp
Battery Replacement for Apple iPhone 4 / iPhone 4S Battery | eBay
Amazon.com: MFI-Apple Certified - ibattz Mojo Vogue Removable Battery Case for iPhone 4 and 4S White 1700mAhX2 fits all version of iPhone 4S/4 : Cell Phones & Accessories
Amazon.com: Winnerplusa Battery for iPhone 4 (3in 1) not Compatible with 4s : Cell Phones & Accessories
iPhone 4S gets dual-core gaming
iPhone 4 Battery - ETrade Supply
SOLVED: Differences between 4 and 4s batteries - iPhone 4S - iFixit