* "Astronomy, A history of man's investigation of the universe", Crescent Books, Inc., London 1962 LC 62-14108* "Galaxies, Nuclei, and Quasars", Harper & Row, Publishers, New York, 1965 LC-65-20996* "Nicolaus Copernicus", Heinemann Educational Books Ltd., London, p. 78, 1973* "Astronomy and Cosmology: A Modern Course", 1975, ISBN 0-7167-0351-3* "Energy or Extinction?
*"Astronomy, A history of man's investigation of the universe", Crescent Books, Inc., London 1962 LC 62-14108*"Galaxies, Nuclei, and Quasars", Harper & Row, Publishers, New York, 1965 LC-65-20996*"Nicolaus Copernicus", Heinemann Educational Books Ltd., London, p. 78, 1973*"Astronomy and Cosmology: A Modern Course", 1975, ISBN 0-7167-0351-3*"Energy or Extinction?