Sonic the Hedgehog 4 goes episodic this summer - GameSpot

Project Needlemouse revealed as side-scrolling sequel to speedster's original Genesis trilogy; Episode 1 confirmed for Wii, Xbox 360, PS3.
Sonic is back for his fourth installment in the classic 2D series, revamped from the ground up.

Editing Sonic the Hedgehog 2006 (lost build of Tokyo Toy Show tech

Sonic 4 Episode 1 » SEGAbits - #1 Source for SEGA News

Sonic the Hedgehog 4: Episode 1 - Game - Nintendo World Report

Sonic the Hedgehog 4: Episode I (Game) - Giant Bomb

Sonic the Hedgehog 4: Episode II, Sonic Wiki Zone

Sonic 4 » SEGAbits - #1 Source for SEGA News

Sonic, Fiction Wiki

The History of Sonic the Hedgehog: The Revival Era - LevelSkip

Sonic the Hedgehog 4: Episode 1 News - GameSpot

Sonic the Hedgehog 4: Episode II, Sonic Wiki Zone