Liu, Y;
Liu, XW;
Barlow, MJ;
Luo, SG;
(2004)
Chemical abundances of planetary nebulae from optical recombination lines – II. Abundances derived from collisionally excited lines and optical recombination lines.
Monthly Notices of the Royal Astronomical Society
, 353
(4)
pp. 1251-1285.
10.1111/j.1365-2966.2004.08156.x.