Who played Norm Peterson in 'Cheers'?

Who played Michael Knight in 'Knight Rider'? Who played Sam Malone in 'Cheers'? Who played Diane Chambers in 'Cheers'? In which TV series is Diane Chambers a main character? In which TV series is Norm Peterson a main character? Who played Cliff Clavin in 'Cheers'? In which TV series is Cliff Clavin a main character? Who played Carla Tortelli in 'Cheers'?