Bender, R., Kormendy, J., Bower, G., Green, R., Thomas, J., Danks, A. C., et al. (2005). HST STIS spectroscopy of the triple nucleus of M31: two nested disks in keplerian rotation around a supermassive black hole. The Astrophysical Journal, 631(1 Part 1), 280-300. doi:10.1086/432434.