Cosmos, episode 1 (1980) Episode 1: The Shores of the Cosmic Ocean (Cosmos: A Personal Voyage, Carl Sagan) "First Galaxies Born Sooner After Big Bang Than Thought".
Truy cập ngày 15 tháng 12 năm 2007.  ^ Cosmos, episode 1 (1980) ^ Episode 1: The Shores of the Cosmic Ocean (Cosmos: A Personal Voyage, Carl Sagan) ^ “First Galaxies Born Sooner After Big Bang Than Thought”.