Table 3: Best-fit parameters of the power-law plus four Gaussians model reproducing the [18-20] Å  RGS-1 spectra of Mkn 421. The error bars refer to the 90% confidence intervals.

RGS-1 [18-20] Å
Feature		FWHM	k
number	(Å)	(mÅ)	( cts cm-2 s-1 Å-1)
ToO observation
2
3
5
6
Archival data
2
3
5
6
Total
2
3
5
6