Galaxy zoo 2: Detailed morphological classifications for 304 122 galaxies from the sloan digital sky survey

Kyle W Willett, Chris J. Lintott, Steven P. Bamford, Karen L. Masters, Brooke D. Simmons, Kevin R.V. Casteels, Edward M. Edmondson, Lucy F Fortson, Sugata Kaviraj, William C. Keel, Thomas Melvin, Robert C. Nichol, M. Jordan Raddick, Kevin Schawinski, Robert J. Simpson, Ramin A. Skibba, Arfon M. Smith, Daniel Thomas