Goldstone and Arecibo radar observations of (99942) Apophis in 2012–2013

Marina Brozović, Lance A.M. Benner, Joseph G. McMichael, Jon D. Giorgini, Petr Pravec, Petr Scheirich, Christopher Magri, Michael W. Busch, Joseph S. Jao, Clement G. Lee, Lawrence G. Snedeker, Marc A. Silva, Martin A. Slade, Boris Semenov, Michael C. Nolan, Patrick A. Taylor, Ellen S. Howell, Kenneth J. Lawrence