[O III]λλ4959,5007 emission complex in velocity space centered around 5006.8 Å (top) and same for [O I]λλ6300,6364 centered around 6300 Å (second panel). The oxygen lines of SN1979C with the addition of [O II]λλ7320,7330 centered at 7320 Å (third panel) and the same lines for SNR 4303-5 (bottom panel). The spectra are normalized arbitrarily to have similar peak intensities. Corresponding figures to other O-rich SNRs are presented in Appendix D.