Troyer, Jon; Starkey, David; Cackett, Edward M.; Bentz, Misty C.; Goad, Michael R.; Horne, Keith; Seals, James E. Correlated X-ray/ultraviolet/optical variability in NGC 6814. Monthly Notices of the Royal Astronomical Society. 14 January 2016, 456 (4): 4040–4050. arXiv:1509.01124. doi:10.1093/mnras/stv2862.
Troyer, Jon; Starkey, David; Cackett, Edward M.; Bentz, Misty C.; Goad, Michael R.; Horne, Keith; Seals, James E. Correlated X-ray/ultraviolet/optical variability in NGC 6814. Monthly Notices of the Royal Astronomical Society. 14 January 2016, 456 (4): 4040–4050. arXiv:1509.01124. doi:10.1093/mnras/stv2862.
spacetelescope.org
A spiral snowflake. www.spacetelescope.org. 9 May 2016 [13 March 2017]. (原始内容存档于2017-12-30).