On the widths and ratios of Mg X 609.79 and 624.94 Å lines in polar off-limb regions E. O'Shea, D. Banerjee and J. G. Doyle A&A, 436 2 (2005) L35-L38 Published online: 30 May 2005 DOI: 10.1051/0004-6361:200500120