Smith, M P Letters between M P Smith and Penrose regarding his article in the <i>Scientific American</i>, and Smith's request to see the models used. Penrose's reply advises that the models cannot be viewed at present, but offers to send copies of his other articles on the subject in <i>Nature</i>, <i>Annals of Human Genetics</i>, and <i>New Biology</i>. Dec 1959 - Feb 1960