Publicado en: Proceedings of the Fourth Berkeley Symposium on Mathematical Statistics and Probability (June 20-July 30 1960), Volume I: Contributions to the theory of statistics, pages 611-644.
Publicado en: Deep Space Network Progress Report, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA - DSN PR 42-44, January and February 1978, pp. 114-116.