Given the question: Information: - The Daleks (also known as The Mutants and The Dead Planet) is the second serial in the British science fiction television series "Doctor Who", which was first broadcast in seven weekly parts from 21 December 1963 to 1 February 1964. It is the first serial to be entirely set on an alien planet. It was written by Terry Nation and directed by Christopher Barry and Richard Martin. This story marks the first appearance of the Doctor's greatest extraterrestrial enemies, the Daleks, and is also the first to feature recurring Skaro people, the Thals. - The Daleks are a fictional extraterrestrial race of mutants principally portrayed in the British science fiction television programme "Doctor Who". The Daleks were conceived by science-fiction writer Terry Nation and first appeared in the 1963 "Doctor Who" serial "The Daleks", in the shells designed by Raymond Cusick. - Doctor Who is a British science-fiction television programme produced by the BBC since 1963. The programme depicts the adventures of a Time Lord called "The Doctor", an extraterrestrial being from the planet Gallifrey. He explores the universe in a time-travelling space ship called the TARDIS. Its exterior appears as a blue British police box, which was a common sight in Britain in 1963 when the series first aired. Accompanied by a number of companions, the Doctor combats a variety of foes, while working to save civilisations and help people in need. - The Power of the Daleks is the completely missing third serial of the fourth season in the British science fiction television series Doctor Who , which was first broadcast in six weekly parts from 5 November to 10 December 1966 . It is the first full story to feature Patrick Troughton as the Second Doctor . Although audio recordings , still photographs , and clips of the story exist , no episodes of this serial are known to have survived . What is the relationship between 'the power of the daleks' and 'christopher barry'?
The answer is:
director