Far-ultraviolet imaging of the globular cluster NGC 6681 with WFPC2

Alan M. Watson, Jeremy R. Mould, John S. Gallagher, Gilda E. Ballester, Christopher J. Burrows, Stefano Casertano, John T. Clarke, David Crisp, Richard E. Griffiths, J. Jeff Hester, John G. Hoessel, Jon A. Holtzman, Paul A. Scowen, Karl R. Stapelfeldt, John T. Trauger, James A. Westphal