Question: Do director of film The Phantom Planet and director of film Swimming to Cambodia have the same nationality?
Sentence (from "The Phantom Planet"): The Phantom Planet is a 1961 independently made American black- and- white science fiction film, produced by Fred Gebhardt, directed by William Marshall, that stars Dean Fredericks, Coleen Gray, Anthony Dexter, and Francis X. Bushman.
Relevant evidence: Yes