The hydrogen-deficient knot of the 'born again' planetary nebula Abell 58 (V605 Aql) Wesson, R. ; Barlow, M. J. ; Liu, X. -W. ; Storey, P. J. ; Ercolano, B. ; De Marco, O. Abstract Publication: Asymmetrical Planetary Nebulae IV Pub Date: June 2007 Bibcode: 2007apn4.confE..21W