New Distances to Four Supernova Remnants
  Distances are found for four supernova remnants without previous distance
measurements. H I spectra and H I channel maps are used to determine the
maximum velocity of H I absorption for the four supernova remnants (SNRs). We
examined $^{13}$CO emission spectra and channel maps to look for possible
molecular gas associated with each SNR, but did not find any. The resulting
distances for the SNRs are $3.5 \pm 0.2$ kpc (G24.7+0.6), $4.7 \pm 0.3$ kpc
(G29.6+0.1), $4.1 \pm 0.5$ kpc (G41.5+0.4) and $4.5 \pm 0 .4 - 9.0 \pm 0.4$ kpc
(G57.2+0.8).
