Green Hill Zone - SmashWiki, the Super Smash Bros. wiki
Punchinello - Super Mario Wiki, the Mario encyclopedia
Ring (Paramount), Sonic Wiki Zone
Sonic Ring PNG Cutout - PNG All, sonic sprite png
Press Garden Zone - Sonic Retro
Sonic 2: Advanced Edit - Sonic Retro
Sonic the Hedgehog/Gallery, Sonic Wiki Zone, classic sonic artwork
Red Star Ring/Gallery, Sonic Wiki Zone
Sonic the Hedgehog - Wikipedia
Sonic X-treme - Wikipedia
World Ring/Gallery, Sonic Wiki Zone
Sonic the Hedgehog (8-bit) (Video Game) - TV Tropes