Uplink-Downlink: A History of the Deep Space Network, 1957–1997 (NASA SP-2001-4227), page 5 NASA (2005).
Архів оригіналу за 2013-03-23.  Uplink-Downlink: A History of the Deep Space Network, 1957—1997 (NASA SP-2001-4227), page 5 NASA (2005).