ペイル・ブルー・ドット
Sagan, Carl; Head, Tom (2006). Conversations with Carl Sagan (1st ed.). United States of America: The University Press of Mississippi. ISBN 1-57806-736-7. https://books.google.co.jp/books?id=gJ1rDj2nR3EC&printsec=frontcover&dq=%22Conversations+with+Carl+Sagan%22&redir_esc=y&hl=ja#v=onepage&q&f=false
Sagan, Carl; Freeman J., Dyson; Jerome, Agel (2000). Carl Sagan's Cosmic Connection:An Extraterrestrial Perspective. Cambridge University Press. pp. XV,302. ISBN 0-521-78303-8. https://books.google.co.jp/books?id=lL57o9YB0mAC&printsec=frontcover&dq=carl+sagan%27s+cosmic+connection+an+extraterrestrial+perspective&redir_esc=y&hl=ja#v=onepage&q&f=false