First X-ray source discovered: from the original paper by
Giacconi et al. 1962, "Evidence for Rontgen-rays from sources outside
the solar system", Phys. Rev. Lett. 9, 439, http://adsabs.harvard.edu/abs/1962PhRvL...9..439G
Material falling around: from Flannery 1975, "The location of the
hot spot in cataclysmic variable stars as determined from particle
trajectories", MNRAS 170, 325, http://adsabs.harvard.edu/abs/1975MNRAS.170..325F
Double pulsar image and animations: from "First-known double
pulsar opens up new astrophysics", Jodrell Bank Press Release 2004/01,
http://www.jb.man.ac.uk/news/doublepulsar/