%0 Generic %A McClintock, William E., %E Vervack, Ronald J., Jr., %E Cassidy, Timothy A., %E Burger, Matthew H. , %E Killen, Rosemary M., %E Merkel, Aimee W., %E Sarantos, Menelaos, %T Mercury's Seasonal Sodium Exosphere : MESSENGER Orbital Observations. %U http://hdl.handle.net/2060/20150010117