5x03: One Small Step (1)
4x20: The Green Machine
4x19: The New Healers
4x16: Tongues of Men (2)
4x15: Tongues of Men (1)
4x14: The Red Planet
4x11: The Wolf Equation
4x10: The Human Animal
4x09: The Gene Engineers
4x08: The Pill for the People
4x07: Bye Bye Blackbird
4x05: The Plastic Prison
4x04: The Sunspot Mystery
4x03: What Price Coal?