NASA Pluto factsheet and NASA Solar System Exploration Pluto Factsheet Retrieved on 2008-11-17 (unless otherwise cited) (i) Lockwood, Alexandra C.; Brown, Michael (Mike) E.; Stansberry, John A. (2014).
2008년 11월 17일에 확인함.  NASA Pluto factsheet and NASA Solar System Exploration Pluto Factsheet Retrieved on 2008-11-17 (unless otherwise cited) (i) Lockwood, Alexandra C.; Brown, Michael (Mike) E.; Stansberry, John A. (2014).